Education

Teaching and learning about math, Maple and MapleSim

The Proceedings of the Maple Conference 2022 are up at mapletransactions.org and I hope that you will find the articles interesting.  There is a brief memorial to Eugenio Roanes-Lozano, whom some of you will remember from past meetings. 

The cover image was the "People's Choice" from the Art Gallery, by Paul DeMarco.

This provides a nice excuse to remind you to register at the conference page for the Maple Conference 2023 and in particular to remind you to submit your entries for the Art Gallery.  See you there!  The conference will take place October 26 and 27, and features plenary talks by our own Laurent Bernardin and by Tom Crawford (Oxford, but more widely known as "The Naked Mathematician" for his incredibly popular YouTube videos on mathematical topics). See Tom Rocks Maths for more (or less :)

The deadline for submission to the Proceedings (which will again be published in Maple Transactions) will be Nov 27, one month after the conference ends.  We have put new processes in place to ensure a more timely publication schedule, and we anticipate that the Proceedings will be published in early Spring 2024.

What are planes? Are they aircraft that soar through the sky, or flat surfaces you'd come across in your geometry textbook? By definition yes, but they can be so much more. In the world of math, observing a system of equations with three variables allows us to plot them as planes in ℝ3. As we plot planes, these geometric entities can start intersecting, creating captivating visualizations. However, the intersection of planes is not just an abstract mathematical concept present only in the classroom. Throughout our daily lives, we come into contact with intersecting planes everywhere. Have you ever noticed the point where two walls and the floor in your room converge? That’s an intersection in its simplest form! And the line where the pages of a book are bound together? Another everyday intersection!
 

Room image: https://unsplash.com/photos/0H-aJ06IZw4, Book image: https://unsplash.com/photos/6H9H-tYPUQQ 

However, just seeing plane intersections is but a tiny piece of the puzzle. After all, how can we delve into the intriguing properties of these intersections without quantifying them? Enter the focus of Maple Learn's newest collection: Intersection of Planes. Not sure about how you can identify the different scenarios that three planes can form in ℝ3? Check out the eight documents that provide complete walk-throughs for solving each individual case that three planes can form! With cases ranging from three parallel and distinct planes to three planes forming a triangular prism to three planes intersecting in a line, you’ll gain a mastery of understanding the intersection of planes by the time you’re finished with the examples.


 

Once you’ve gained an understanding of how to identify and solve the cases that three planes can form, it’s time to test your knowledge! This quiz-like document takes you through the steps of solving for the intersection of three planes with guiding questions and comprehensive feedback. Once you successfully find the intersection or identify the case, you’ll be provided with an interactive 3D plot that allows you to see what the math you’ve been doing looks like. This opportunity to solve any of the 16 different possible systems of equations allows you to prove that you’re on another level!


With your newfound mastery of solving systems of equations, check out similar documents in the recently added linear algebra collection! Try calculating the volume of a parallelepiped or deriving the formula for the distance between a point and a plane

What are you waiting for? Gear up and join us on Maple Learn today! Whether you're diving deep into the world of linear algebra or merely dabbling, there’s a world of discovery waiting for you.

Jill is walking on some trails after a long and stressful day at work. Suddenly, her stress seems to be lifted off her shoulders as her attention gets drawn to nature's abundant beauty. From the way the flowers blossom to the way the leaves grow on their stems, it is stunning.

When many think of mathematics, what comes to mind is often numbers, equations, and calculations. While these aspects are essential to math, they only scratch the surface of a profoundly creative discipline. Mathematics is much more than mere numerical manipulation. It is a rich and intricate realm that influences everything from art and science to philosophy and technology.

Just as Jill was stunned by the beauty of nature, you too can be amazed by the beauty of math! The golden ratio is one math concept that garners a reputation for being particularly beautiful, perhaps due to its presence in different parts of nature. You can explore it through some Maple Learn documents.

Check out the Fibonacci sequence and golden ratio document to better understand the golden ratio and its relationships. Perhaps, once you have a good grasp on the basics, you would like to check out the golden spiral document. Notice how the spiral that results resembles the outline of a nautilus shell and the arms of a spiral galaxy!

The spiral generated in the maple learn document on the golden spiral. A nautilus shell whose shape resembles the golden spiral generated in the maple learn document.A spiral galaxy whose arms resemble the spiral generated in the Maple Learn document on the golden spiral.

Nautilus shell image: https://en.wikipedia.org/wiki/File:NautilusCutawayLogarithmicSpiral.jpg -- Spiral galaxy image: https://www.cnet.com/pictures/natures-patterns-golden-spirals-and-branching-fractals/


Next, you may want to understand why the golden ratio is considered the most irrational number. You can do that by checking out the most irrational number document. Or you could explore this golden angle document to see how the irrationality of the number can be used to reproduce structures found in nature, such as the arrangement of seeds in a sunflower's centre!


An image generated in the golden angle Maple Learn document where points are packed around the center of a circle using the golden angle. The points are tightly packed around the center.The previous image is superimposed on top of an image of the center of a sunflower. The superimposed image matches the seeds' packing in the sunflower's center.

Sunflower image: https://commons.wikimedia.org/wiki/File:Helianthus_whorl.jpg
 

That's all for this post! No worries, though. Maple Learn has hundreds of documents that can aid you in exploring the abundant beauty of math. Enjoy!

 

Advanced Engineering Mathematics with Maple (AEM) by Dr. Lopez is such an art.

Mathematics and Control Theory talks easily in Maple...

Thanks Prof. Lopez. You are the MAN !!

Dr. Ali GÜZEL

Registration for Maple Conference 2023 is now open! This year’s conference will again be a free virtual event. Please visit our site to see more information about the event and to register.

Our call for presentations has now concluded, but it is not too late to submit to our Maple Conference Art Gallery and Creative Works Showcase.

The Agenda section, where you’ll find information about the conference format and an overview schedule, has been added. This will be updated as the details are finalized.  

The pendulum and the cantilever share simple-looking ordinary differential equations (ODEs), but they are challenging to solve:

This post derives solutions from Lawden and Bisshopp by Maple commands, which (to the best of my knowledge) have not been published providing not only results but also the accompanying computer algebra techniques. A tabulated format has been chosen to better highlight similarities and differences.

Both solutions have in common that in a first step, the unknown function is integrated and then in a second step the inverse of the unknown function (i.e., the independent variable) is integrated. Only in combination with a well-chosen set of initial/boundary conditions solutions are possible. This makes these two cases difficult to handle by generic integration methods.

Originally, I was not looking for this insight. I was more interested in an exact solution for nonlinear deformations to benchmark numerical simulation results.  Relatively quickly, I was able to achieve this with the help of this forum, but after that I was left with some nagging questions:

Why does Maple not provide a solution for the pendulum although one exists?

Why isn’t there an explicit solution for the cantilever when there is one for the pendulum?

Why is it so difficult to proof that elliptic expressions are equal?

Repeatedly, whenever there was time, I came back to these questions and got more and more a better understanding of the two problems and the overall context. It also required me to learn more of Maple, and I had to revisit fundamentals of functions, differential equations, and integration, which was entirely possible within Maples help system. Today, I am satisfied to the point that I think it is too much to expect Maple to provide a high-level general integration method for such problems.

I am also satisfied that I was able to combine all my findings scattered across many documents and Mapleprime questions into a single executable textbook-style document with hidden Maple code that:

Exclusively uses and manipulates equation expressions (no assignment operators := were required),

Avoids differentials that are often used in textbooks but (for good reasons) are not supported by Maple,

Exclusively applies high-level commands (i.e. no extraction of subexpression, manipulation
           and subsequent re-assembly of expressions was needed).

The solutions for the pendulum and the cantilever are substantially different although the ODEs and essential derivation steps are similar. I think that an explicit solution for the cantilever, as it exists for the pendulum, is impossible (using elliptic integrals and functions). I leave it open to comments: whether this is correct and whether it is attributable to the set of initial and boundary conditions, the different symmetry of the sine and cosine functions in the ODEs, or both. I hope that the tabular presentation will provide an easy overview, allowing to form an own opinion.

If you are patient enough to work through the table, you will find a link between the cantilever and the pendulum that you are probably not expecting. 

Finally, I have to give credit to Bisshopp, who was probably the first to provide a solution for the cantilever. The clarity and compactness on only 3 pages and the way how the inverse of functions was determined before the age of computers makes this paper worth studying. Also, Lawden has to be mentioned, who did the same on 3 pages for the pendulum in a marvelous book on elliptic functions and applications. It happens that he is overlooked in more recent publications and it’s unclear to me if he was the first who published an explicit solution. His book might be one of the last of its kind in this age of computers, and for that reason alone, it is worth enjoying as he enjoyed writing it.

 

The Pendulum and the Cantilever Side by Side

C_R, Summer 2023

• 

To better compare the pendulum and the cantilever, the symbol `ϕ` was chosen for the angle of the pendulum for the simple reason that this comparison started with bending theory, where `ϕ` is often used to denote a deflection angle.

• 

Leibniz and Newton notation was not used to make functional dependencies of variables visible. Instead functional notation  `ϕ` = `ϕ`(t) and `ϕ` = `ϕ`(s)is used.

• 

To create an executable document that maintains a clear representation, it is necessary to use functional notation for differential equations and remove functional notation for integration. To avoid using the same symbol for both the integration variable and the upper limit of integration, this document uses two ways to express when the upper limit of integration varies (i.e., depends on the dependent variable of the functions being searched, namely `ϕ` = `ϕ`(t) and `ϕ` = `ϕ`(s)). Both ways have their pros and cons.

 

Typesetting:-EnableTypesetRule({"EllipticE", "EllipticE2", "EllipticF", "EllipticK", "InverseJacobiAM", "InverseJacobiSN", "JacobiSN"})

 

©_®

Pendulum

Cantilever

Independent variable

Time t

Arclength s

Dependent variable

Angle of the pendulum with respect to direction of gravity `ϕ`(t)

varphi(t)

(1)

The slope of the cantilever with respect to the unbend state `ϕ`(s)

varphi(s)

(2)

Parameters

• 

Length l

• 

Gravitational constant g 

• 

Length L

• 

A force F at the free end

• 

A bending moment M at the free end

• 

The bending stiffness EI 

ODE

diff(varphi(t), t, t)+C*sin(varphi(t)) = 0

diff(diff(varphi(t), t), t)+C*sin(varphi(t)) = 0

(3)

(for derivation see for example Wikipedia [1] or Lawden [2])

diff(varphi(s), s, s)+C*cos(varphi(s)) = 0

diff(diff(varphi(s), s), s)+C*cos(varphi(s)) = 0

(4)

(for derivation see for example Bisshopp [3] or Beléndez [4])

Definitions

`ϕ`(0) = 0, `ϕ`((1/4)*T) = `ϕ__0`

varphi(0) = 0, varphi((1/4)*T) = varphi__0

(5)

`ϕ`(t)is periodic with the oscillation period T (i.e., the movement is bounded):

0 < abs(`&varphi;__0`) and abs(`&varphi;__0`) < Pi

0 < abs(varphi__0) and abs(varphi__0) < Pi

(6)

`&varphi;`(L) = `&varphi;__0`, Eval(diff(varphi(s), s), s = L) = 1/rho

varphi(L) = varphi__0, Eval(diff(varphi(s), s), s = L) = 1/rho

(7)

For a downward force:

0 < `&varphi;__0` and `&varphi;__0` < (1/2)*Pi

0 < varphi__0 and varphi__0 < (1/2)*Pi

(8)

Parameter C

"C=omega^(2)", where omegais the angular frequency of the pendulum for small anglular excursions

C = g/l

C = g/l

(9)

"Specific" Load

C = F/EI

C = F/EI

(10)

Initial/

boundary
conditions

Eval(varphi(t), t = -(1/4)*T) = -`&varphi;__0`, Eval(diff(varphi(t), t), t = -(1/4)*T) = 0

Eval(varphi(t), t = -(1/4)*T) = -varphi__0, Eval(diff(varphi(t), t), t = -(1/4)*T) = 0

(11)

Eval(varphi(s), s = 0) = 0, varphi(L) = varphi__0, Eval(diff(varphi(s), s), s = L) = 1/rho

Eval(varphi(s), s = 0) = 0, varphi(L) = varphi__0, Eval(diff(varphi(s), s), s = L) = 1/rho

(12)

Only the second condition is essential.
Additional essential condition: The length L of the cantilever beam is constant (not a boundary condition in its common sense but essential for the solution).

#1 integration step
with the second condition

Method: Integration with an integration factor (and converting to D notation, not shown)

DEtools:-intfactor(diff(diff(varphi(t), t), t)+C*sin(varphi(t)) = 0, `&varphi;`(t)); DETools:-firint((diff(diff(varphi(t), t), t)+C*sin(varphi(t)) = 0)*%, `&varphi;`(t))

-2*C*cos(varphi(t))+(diff(varphi(t), t))^2+c__1 = 0

(13)

Substituting initial conditions (11)

eval(convert(-2*C*cos(varphi(t))+(diff(varphi(t), t))^2+c__1 = 0, D), t = -(1/4)*T); convert(value({Eval(diff(varphi(t), t), t = -(1/4)*T) = 0, Eval(varphi(t), t = -(1/4)*T) = -varphi__0}), D); isolate(eval(`%%`, %), c__1)

c__1 = 2*C*cos(varphi__0)

(14)

and isolating diff(`&varphi;`(t), t)in (13) yields

convert(isolate(subs(c__1 = 2*C*cos(varphi__0), -2*C*cos(varphi(t))+(diff(varphi(t), t))^2+c__1 = 0), diff(`&varphi;`(t), t)), radical)

diff(varphi(t), t) = (2*C*cos(varphi(t))-2*C*cos(varphi__0))^(1/2)

(15)

Alternative method [5]: Integration to an implicit representation

dsolve({(Eval(varphi(s), s = 0) = 0, varphi(L) = varphi__0, Eval(diff(varphi(s), s), s = L) = 1/rho)[3], diff(diff(varphi(s), s), s)+C*cos(varphi(s)) = 0}, `&varphi;`(s), implicit)[1]

Int(1/(-2*C*sin(_a)+(2*C*sin(varphi(L))*rho^2+1)/rho^2)^(1/2), _a = 0 .. varphi(s))-s-c__2 = 0

(16)

and differentiation w.r.t. to s 

diff(Int(1/(-2*C*sin(_a)+(2*C*sin(varphi(L))*rho^2+1)/rho^2)^(1/2), _a = 0 .. varphi(s))-s-c__2 = 0, s); isolate(%, diff(`&varphi;`(s), s)); expand(subs(varphi(L) = varphi__0, Eval(diff(varphi(s), s), s = L) = 1/rho, %))

diff(varphi(s), s) = (-2*C*sin(varphi(s))+2*C*sin(varphi__0)+1/rho^2)^(1/2)

(17)

(This method works only if rho <> infinity; i.e., only with curvature/bending moment at the free end.)

Continuing now without bending momenteval(diff(varphi(s), s) = (-2*C*sin(varphi(s))+2*C*sin(varphi__0)+1/rho^2)^(1/2), rho = infinity)

diff(varphi(s), s) = (-2*C*sin(varphi(s))+2*C*sin(varphi__0))^(1/2)

(18)

#2 integrating the inverse function

With the chain rule

(diff(`&varphi;`(t), t))*(diff(t(`&varphi;`), `&varphi;`)) = 1

(diff(varphi(t), t))*(diff(t(varphi), varphi)) = 1

(19)

isolate((diff(varphi(t), t))*(diff(t(varphi), varphi)) = 1, diff(`&varphi;`(t), t))

diff(varphi(t), t) = 1/(diff(t(varphi), varphi))

(20)

(15) can be written as

isolate((diff(varphi(t), t) = 1/(diff(t(varphi), varphi)))*(1/(diff(varphi(t), t) = (2*C*cos(varphi(t))-2*C*cos(varphi__0))^(1/2))), diff(t(`&varphi;`), `&varphi;`)); subs(`&varphi;`(t) = `&varphi;`, %)

diff(t(varphi), varphi) = 1/(2*C*cos(varphi)-2*C*cos(varphi__0))^(1/2)

(21)

where the functional notation `&varphi;`(t)was removed for integration

map(Int, diff(t(varphi), varphi) = 1/(2*C*cos(varphi)-2*C*cos(varphi__0))^(1/2), `&varphi;` = 0 .. `&varphi;`(t), continuous); (`@`(value, lhs) = rhs)(%)

-t(0)+t(varphi(t)) = Int(1/(2*C*cos(varphi)-2*C*cos(varphi__0))^(1/2), varphi = 0 .. varphi(t), continuous)

(22)

This relation allows to determine the time t = t(`&varphi;`(t)) the pendulum takes to swing to a certain angle `&varphi;` = `&varphi;`*t__.

Similarly, with

(diff(`&varphi;`(s), s))*(diff(s(`&varphi;`), `&varphi;`)) = 1

(diff(varphi(s), s))*(diff(s(varphi), varphi)) = 1

(23)

isolate((diff(varphi(s), s))*(diff(s(varphi), varphi)) = 1, diff(`&varphi;`(s), s))

diff(varphi(s), s) = 1/(diff(s(varphi), varphi))

(24)

(16) can be written as

isolate((diff(varphi(s), s) = 1/(diff(s(varphi), varphi)))*(1/(diff(varphi(s), s) = (-2*C*sin(varphi(s))+2*C*sin(varphi__0))^(1/2))), diff(s(`&varphi;`), `&varphi;`))

diff(s(varphi), varphi) = 1/(-2*C*sin(varphi(s))+2*C*sin(varphi__0))^(1/2)

(25)

and integrated over s

map(int, diff(s(varphi), varphi) = 1/(-2*C*sin(varphi(s))+2*C*sin(varphi__0))^(1/2), `&varphi;` = 0 .. `&varphi;__s`, continuous)

-s(0)+s(varphi__s) = int(1/(-2*C*sin(varphi(s))+2*C*sin(varphi__0))^(1/2), varphi = 0 .. varphi__s, continuous)

(26)

This expression relates the arclength s to the slope `&varphi;__s` at the location s (i.e., `&varphi;`(s) = `&varphi;__s`). It is the inverse of what we intend to solve (i.e., `&varphi;` = `&varphi;`(s)) but it is essential to derive a solution. Unlike for the pendulum, an indexed symbol `#msub(mi("&varphi;",fontstyle = "normal"),mi("s"))`has been chosen to avoid formally correct but uncommon expressions like "t(`&varphi;`(t))."

Special cases

Oscillation period T

When `&varphi;`*t__ = `&varphi;__0` the pendulum has swung a quater of the period. With
t(0) = 0, `&varphi;`(t) = `&varphi;__0`, t(`&varphi;__0`) = (1/4)*T

t(0) = 0, varphi(t) = varphi__0, t(varphi__0) = (1/4)*T

(27)

(22) becomes

subs(t(0) = 0, varphi(t) = varphi__0, t(varphi__0) = (1/4)*T, -t(0)+t(varphi(t)) = Int(1/(2*C*cos(varphi)-2*C*cos(varphi__0))^(1/2), varphi = 0 .. varphi(t), continuous))

(1/4)*T = Int(1/(2*C*cos(varphi)-2*C*cos(varphi__0))^(1/2), varphi = 0 .. varphi__0, continuous)

(28)

where `&varphi;`(t)was replaced in the integrant by `&varphi;` to create input that can be processes by the int command. After evaluation

isolate(`assuming`([simplify(value((1/4)*T = Int(1/(2*C*cos(varphi)-2*C*cos(varphi__0))^(1/2), varphi = 0 .. varphi__0, continuous)))], [C > 0, 0 < `&varphi;__0` and `&varphi;__0` < Pi]), T)

T = 4*2^(1/2)*InverseJacobiAM((1/2)*varphi__0, 2^(1/2)/(1-cos(varphi__0))^(1/2))/(C^(1/2)*(1-cos(varphi__0))^(1/2))

(29)

where 1/am = InverseJacobiAM denotes the inverse Jacobian amplitude function.

Expression for `&varphi;__0`
Calculation of the length L in order to get an expression to determine the unknown slope `&varphi;__0` at the free end of the cantilever as a function of the load parameter C. With
s(0) = 0, s(`&varphi;__s`) = L, `&varphi;__s` = `&varphi;__0`, `&varphi;`(s) = `&varphi;`

s(0) = 0, s(varphi__s) = L, varphi__s = varphi__0, varphi(s) = varphi

(30)

(26) becomessubs(s(0) = 0, s(varphi__s) = L, varphi__s = varphi__0, varphi(s) = varphi, -s(0)+s(varphi__s) = int(1/(-2*C*sin(varphi(s))+2*C*sin(varphi__0))^(1/2), varphi = 0 .. varphi__s, continuous))

L = int(1/(-2*C*sin(varphi)+2*C*sin(varphi__0))^(1/2), varphi = 0 .. varphi__0, continuous)

(31)

where `&varphi;`(s)is replaced by `&varphi;` to create input that can be processes by the int command. After evaluation

`assuming`([value(L = int(1/(-2*C*sin(varphi)+2*C*sin(varphi__0))^(1/2), varphi = 0 .. varphi__0, continuous))], [C > 0, 0 < `&varphi;__0` and `&varphi;__0` < (1/2)*Pi])

L = EllipticK((1/2)*(2*sin(varphi__0)+2)^(1/2))/C^(1/2)-EllipticF(1/(sin(varphi__0)+1)^(1/2), (1/2)*(2*sin(varphi__0)+2)^(1/2))/C^(1/2)

(32)

where K = EllipticK and F = EllipticF denote the complete and incomplete elliptic integrals of the first kind.

#3 Solutions of particular interest  

Explicit solution for `&varphi;`(t) in bounded motion.
Rearranging (22)

`assuming`([simplify(2*C*(-t(0)+t(varphi(t)) = Int(1/(2*C*cos(varphi)-2*C*cos(varphi__0))^(1/2), varphi = 0 .. varphi(t), continuous)))], [C > 0])/(sqrt(C)*sqrt(2))

-C^(1/2)*2^(1/2)*(t(0)-t(varphi(t))) = Int(1/(cos(varphi)-cos(varphi__0))^(1/2), varphi = 0 .. varphi(t), continuous)

(33)

and substituting this essential identity (expression 5.1.3 from Lawden [2])

-cos(`&varphi;__0`)+cos(`&varphi;`) = 2*sin((1/2)*`&varphi;__0`)^2-2*sin((1/2)*`&varphi;`)^2

cos(varphi)-cos(varphi__0) = 2*sin((1/2)*varphi__0)^2-2*sin((1/2)*varphi)^2

(34)

yields

subs(cos(varphi)-cos(varphi__0) = 2*sin((1/2)*varphi__0)^2-2*sin((1/2)*varphi)^2, -C^(1/2)*2^(1/2)*(t(0)-t(varphi(t))) = Int(1/(cos(varphi)-cos(varphi__0))^(1/2), varphi = 0 .. varphi(t), continuous))

-C^(1/2)*2^(1/2)*(t(0)-t(varphi(t))) = Int(1/(2*sin((1/2)*varphi__0)^2-2*sin((1/2)*varphi)^2)^(1/2), varphi = 0 .. varphi(t), continuous)

(35)

`assuming`([value(-C^(1/2)*2^(1/2)*(t(0)-t(varphi(t))) = Int(1/(2*sin((1/2)*varphi__0)^2-2*sin((1/2)*varphi)^2)^(1/2), varphi = 0 .. varphi(t), continuous))], [0 < `&varphi;__0` and `&varphi;__0` < Pi])

-C^(1/2)*2^(1/2)*(t(0)-t(varphi(t))) = 2^(1/2)*InverseJacobiAM((1/2)*varphi(t), csc((1/2)*varphi__0))/sin((1/2)*varphi__0)

(36)

which simplifies further with

t(0) = 0, t(`&varphi;`(t)) = t

t(0) = 0, t(varphi(t)) = t

(37)

to

subs(t(0) = 0, t(varphi(t)) = t, ((-C^(1/2)*2^(1/2)*(t(0)-t(varphi(t))) = 2^(1/2)*InverseJacobiAM((1/2)*varphi(t), csc((1/2)*varphi__0))/sin((1/2)*varphi__0))*(1/sqrt(2)))*sin((1/2)*`&varphi;__0`))

sin((1/2)*varphi__0)*C^(1/2)*t = InverseJacobiAM((1/2)*varphi(t), csc((1/2)*varphi__0))

(38)

Mapping now sn = JacobiSN with the modulus csc((1/2)*`&varphi;__0`) to the expression above (Maple converts InverseJacobiAM to InverseJacobiSN and simplifies automatically)

map(JacobiSN, sin((1/2)*varphi__0)*C^(1/2)*t = InverseJacobiAM((1/2)*varphi(t), csc((1/2)*varphi__0)), csc((1/2)*`&varphi;__0`))

JacobiSN(sin((1/2)*varphi__0)*C^(1/2)*t, csc((1/2)*varphi__0)) = sin((1/2)*varphi(t))

(39)

the angle `&varphi;`as a function of time is obtained explicitly

convert(isolate(JacobiSN(sin((1/2)*varphi__0)*C^(1/2)*t, csc((1/2)*varphi__0)) = sin((1/2)*varphi(t)), `&varphi;`(t)), sincos)

varphi(t) = 2*arcsin(JacobiSN(sin((1/2)*varphi__0)*C^(1/2)*t, 1/sin((1/2)*varphi__0)))

(40)

Bending curve of the cantilever for a given load (i.e., for a given `&varphi;__0`, obtainable from (32)).

To obtain a parametric form x(p), y(p)of the bending curve, the following two ODEs have to be integrated

diff(x(s), s) = cos(`&varphi;`(s)), diff(y(s), s) = sin(`&varphi;`(s))

diff(x(s), s) = cos(varphi(s)), diff(y(s), s) = sin(varphi(s))

(41)

Applying

diff(x(s), s) = (diff(x(`&varphi;`), `&varphi;`))*(diff(`&varphi;`(s), s)), diff(y(s), s) = (diff(y(`&varphi;`), `&varphi;`))*(diff(`&varphi;`(s), s))

diff(x(s), s) = (diff(x(varphi), varphi))*(diff(varphi(s), s)), diff(y(s), s) = (diff(y(varphi), varphi))*(diff(varphi(s), s))

(42)

in the following way to (41)

subs({diff(x(s), s) = (diff(x(varphi), varphi))*(diff(varphi(s), s)), diff(y(s), s) = (diff(y(varphi), varphi))*(diff(varphi(s), s))}, diff(varphi(s), s) = 1/(diff(s(varphi), varphi)), {diff(x(s), s) = cos(varphi(s)), diff(y(s), s) = sin(varphi(s))})[]

(diff(x(varphi), varphi))/(diff(s(varphi), varphi)) = cos(varphi(s)), (diff(y(varphi), varphi))/(diff(s(varphi), varphi)) = sin(varphi(s))

(43)

isolate(((diff(x(varphi), varphi))/(diff(s(varphi), varphi)) = cos(varphi(s)), (diff(y(varphi), varphi))/(diff(s(varphi), varphi)) = sin(varphi(s)))[1], diff(x(`&varphi;`), `&varphi;`)), isolate(((diff(x(varphi), varphi))/(diff(s(varphi), varphi)) = cos(varphi(s)), (diff(y(varphi), varphi))/(diff(s(varphi), varphi)) = sin(varphi(s)))[2], diff(y(`&varphi;`), `&varphi;`))

diff(x(varphi), varphi) = cos(varphi(s))*(diff(s(varphi), varphi)), diff(y(varphi), varphi) = sin(varphi(s))*(diff(s(varphi), varphi))

(44)

yields two ODEs where x and y depend on the variable `&varphi;`(s). Substituting (25) and `&varphi;`(s) = `&varphi;` 

subs(diff(s(varphi), varphi) = 1/(-2*C*sin(varphi(s))+2*C*sin(varphi__0))^(1/2), `&varphi;`(s) = `&varphi;`, [diff(x(varphi), varphi) = cos(varphi(s))*(diff(s(varphi), varphi)), diff(y(varphi), varphi) = sin(varphi(s))*(diff(s(varphi), varphi))])[]

diff(x(varphi), varphi) = cos(varphi)/(-2*C*sin(varphi)+2*C*sin(varphi__0))^(1/2), diff(y(varphi), varphi) = sin(varphi)/(-2*C*sin(varphi)+2*C*sin(varphi__0))^(1/2)

(45)

map(Int, (diff(x(varphi), varphi) = cos(varphi)/(-2*C*sin(varphi)+2*C*sin(varphi__0))^(1/2), diff(y(varphi), varphi) = sin(varphi)/(-2*C*sin(varphi)+2*C*sin(varphi__0))^(1/2))[1], `&varphi;` = 0 .. `&varphi;__s`, continuous), map(Int, (diff(x(varphi), varphi) = cos(varphi)/(-2*C*sin(varphi)+2*C*sin(varphi__0))^(1/2), diff(y(varphi), varphi) = sin(varphi)/(-2*C*sin(varphi)+2*C*sin(varphi__0))^(1/2))[2], `&varphi;` = 0 .. `&varphi;__s`, continuous)

Int(diff(x(varphi), varphi), varphi = 0 .. varphi__s, continuous) = Int(cos(varphi)/(-2*C*sin(varphi)+2*C*sin(varphi__0))^(1/2), varphi = 0 .. varphi__s, continuous), Int(diff(y(varphi), varphi), varphi = 0 .. varphi__s, continuous) = Int(sin(varphi)/(-2*C*sin(varphi)+2*C*sin(varphi__0))^(1/2), varphi = 0 .. varphi__s, continuous)

(46)

results in a parametric solution with parameter `#mrow(mi("p"),mo("&equals;"),mi("\`&varphi;__s\`"))` where "0<= `&varphi;__s`<=`&varphi;__0`." 
For the x coordinate

subs(`assuming`([x(0) = 0, simplify(value((Int(diff(x(varphi), varphi), varphi = 0 .. varphi__s, continuous) = Int(cos(varphi)/(-2*C*sin(varphi)+2*C*sin(varphi__0))^(1/2), varphi = 0 .. varphi__s, continuous), Int(diff(y(varphi), varphi), varphi = 0 .. varphi__s, continuous) = Int(sin(varphi)/(-2*C*sin(varphi)+2*C*sin(varphi__0))^(1/2), varphi = 0 .. varphi__s, continuous))[1]))], [0 < `&varphi;` and `&varphi;` < (1/2)*Pi, C > 0]))

x(varphi__s) = (2^(1/2)*sin(varphi__0)^(1/2)-(-2*sin(varphi__s)+2*sin(varphi__0))^(1/2))/C^(1/2)

(47)

For the y coordinate a long expression with the following structure

subs(`assuming`([y(0) = 0, simplify(value((Int(diff(x(varphi), varphi), varphi = 0 .. varphi__s, continuous) = Int(cos(varphi)/(-2*C*sin(varphi)+2*C*sin(varphi__0))^(1/2), varphi = 0 .. varphi__s, continuous), Int(diff(y(varphi), varphi), varphi = 0 .. varphi__s, continuous) = Int(sin(varphi)/(-2*C*sin(varphi)+2*C*sin(varphi__0))^(1/2), varphi = 0 .. varphi__s, continuous))[2]), radical)], [0 < `&varphi;` and `&varphi;` < (1/2)*Pi, 0 < `&varphi;__0` and `&varphi;__0` < (1/2)*Pi, 0 < `&varphi;__s` and `&varphi;__s` < (1/2)*Pi, C > 0])); y(`&varphi;__s`) = (A__1*EllipticE(z__1, k)+A__2*EllipticF(z__1, k)+A__3*EllipticE(z__2, k)+A__4*EllipticF(z__2, k))/sqrt(C)

y(varphi__s) = (A__1*EllipticE(z__1, k)+A__2*EllipticF(z__1, k)+A__3*EllipticE(z__2, k)+A__4*EllipticF(z__2, k))/C^(1/2)

(48)

is obtained where A__i = A__i(`&varphi;__s`, `&varphi;__0`), z__i = z__i(`&varphi;__s`, `&varphi;__0`) and k = k(`&varphi;__0`).

NULL

Not required in the above: To derive an explicit solution, Lawden performed a change of variable of this kind

sin((1/2)*`&varphi;`) = sin((1/2)*`&varphi;__0`)*sin(u)

sin((1/2)*varphi) = sin((1/2)*varphi__0)*sin(u)

(49)

 

which is not needed with Maple commands.

 

Furthermore: Formally, it would have been nice to have the pendulum start its movement at t=0 at an angle -`&varphi;__0`. However, this leads to an output in (36) with two inverse elliptic functions where `&varphi;`(t) is difficult if not impossible to isolate.

 

Solution for the free end of the cantilever (i.e., `&varphi;__s` = `&varphi;__0`and s = L)

subs(x(0) = 0, `&varphi;__s` = `&varphi;__0`, x(`&varphi;__0`) = x(L), x(varphi__s) = (2^(1/2)*sin(varphi__0)^(1/2)-(-2*sin(varphi__s)+2*sin(varphi__0))^(1/2))/C^(1/2))

x(L) = 2^(1/2)*sin(varphi__0)^(1/2)/C^(1/2)

(50)

subs(`assuming`([y(0) = 0, y(`&varphi;__0`) = y(L), simplify(value(subs(`&varphi;__s` = `&varphi;__0`, (Int(diff(x(varphi), varphi), varphi = 0 .. varphi__s, continuous) = Int(cos(varphi)/(-2*C*sin(varphi)+2*C*sin(varphi__0))^(1/2), varphi = 0 .. varphi__s, continuous), Int(diff(y(varphi), varphi), varphi = 0 .. varphi__s, continuous) = Int(sin(varphi)/(-2*C*sin(varphi)+2*C*sin(varphi__0))^(1/2), varphi = 0 .. varphi__s, continuous))[2])))], [0 < `&varphi;` and `&varphi;` < (1/2)*Pi, 0 < `&varphi;__0` and `&varphi;__0` < (1/2)*Pi, 0 < `&varphi;__s` and `&varphi;__s` < (1/2)*Pi, C > 0]))

y(L) = (EllipticK((1/2)*(2*sin(varphi__0)+2)^(1/2))-EllipticF(1/(sin(varphi__0)+1)^(1/2), (1/2)*2^(1/2)*(sin(varphi__0)+1)^(1/2))-2*EllipticE((1/2)*2^(1/2)*(sin(varphi__0)+1)^(1/2))+2*EllipticE(1/(sin(varphi__0)+1)^(1/2), (1/2)*2^(1/2)*(sin(varphi__0)+1)^(1/2)))/C^(1/2)

(51)

``

Some remarks

NULL

NULL

 

Comparison to the solution from Lawden

Expression (39) compared to sin((1/2)*theta(t)) = sin((1/2)*alpha)*sn(t+K, sin((1/2)*alpha))

sin((1/2)*theta(t)) = sin((1/2)*alpha)*sn(t+K, sin((1/2)*alpha))

(52)

(pasted from DLMF 22.19.2 for the case C = 1). The same with adapted variables  subs(alpha = `&varphi;__0`, sn = JacobiSN, K = 0, theta(t) = `&varphi;__t`, sin((1/2)*theta(t)) = sin((1/2)*alpha)*sn(t+K, sin((1/2)*alpha)))

sin((1/2)*varphi__t) = sin((1/2)*varphi__0)*JacobiSN(t, sin((1/2)*varphi__0))

(53)

Now equating the left hand side of (39) to JacobiSN(z, k)and identifying the parameters z and k

subs(C = 1, lhs(JacobiSN(sin((1/2)*varphi__0)*C^(1/2)*t, csc((1/2)*varphi__0)) = sin((1/2)*varphi(t)))) = JacobiSN(z, k)

JacobiSN(sin((1/2)*varphi__0)*t, csc((1/2)*varphi__0)) = JacobiSN(z, k)

(54)

map(op, JacobiSN(sin((1/2)*varphi__0)*t, csc((1/2)*varphi__0)) = JacobiSN(z, k)); solve([(rhs-lhs)(%)], {k, z})[]

k = csc((1/2)*varphi__0), z = sin((1/2)*varphi__0)*t

(55)

Using the following identity from Maple's FunctionAdvisor and the correspondence in (55)

FunctionAdvisor(identities, JacobiSN(z, 1/k))[5]

JacobiSN(z, k) = JacobiSN(z*k, 1/k)/k

(56)

yields

convert(subs(k = csc((1/2)*varphi__0), z = sin((1/2)*varphi__0)*t, JacobiSN(z, k) = JacobiSN(z*k, 1/k)/k), sincos)

JacobiSN(sin((1/2)*varphi__0)*t, 1/sin((1/2)*varphi__0)) = sin((1/2)*varphi__0)*JacobiSN(t, sin((1/2)*varphi__0))

(57)

Comparing this with (53) confirms that (40) is correct.

Equivalent expressions to determine `&varphi;__0` 

As returned by value:

normal(L = EllipticK((1/2)*(2*sin(varphi__0)+2)^(1/2))/C^(1/2)-EllipticF(1/(sin(varphi__0)+1)^(1/2), (1/2)*(2*sin(varphi__0)+2)^(1/2))/C^(1/2))

L = (EllipticK((1/2)*(2*sin(varphi__0)+2)^(1/2))-EllipticF(1/(sin(varphi__0)+1)^(1/2), (1/2)*(2*sin(varphi__0)+2)^(1/2)))/C^(1/2)

(58)

simplify instead of value:

convert(`assuming`([simplify(L = int(1/(-2*C*sin(varphi)+2*C*sin(varphi__0))^(1/2), varphi = 0 .. varphi__0, continuous))], [0 < `&varphi;__0` and `&varphi;__0` < (1/2)*Pi]), sincos)

L = -I*2^(1/2)*EllipticF(I*sin(varphi__0)^(1/2)/(1-sin(varphi__0))^(1/2), I*(1-sin(varphi__0))^(1/2)/(sin(varphi__0)+1)^(1/2))/(C^(1/2)*(sin(varphi__0)+1)^(1/2))

(59)

With integration tools and change of variables using x = sin(`&varphi;`):

Int(1/sqrt(-2*C*sin(`&varphi;`)+2*C*sin(`&varphi;__0`)), `&varphi;` = 0 .. `&varphi;__0`); L = IntegrationTools:-Change(%, x = sin(`&varphi;`), x); simplify(subs(isolate(x__0 = sin(`&varphi;__0`), `&varphi;__0`), %)); subs(x__0 = sin(`&varphi;__0`), `assuming`([value(%)], [0 < x and x < 1, 0 < x__0 and x__0 < 1]))

L = 2^(1/2)*EllipticF(sin(varphi__0)^(1/2)/(sin(varphi__0)+1)^(1/2), I*(-sin(varphi__0)^2+1)^(1/2)/(-1+sin(varphi__0)))/(C^(1/2)*(1-sin(varphi__0))^(1/2))

(60)

Without having a Maple way: Christian Wolinski has provided 3 additional expressions where one is of particular simplicity [6]

  L = EllipticF(sqrt(1-1/(sin(`&varphi;__0`)+1))*sqrt(2), (1/2)*sqrt(2)*sqrt(sin(`&varphi;__0`)+1))/sqrt(C)

L = EllipticF((1-1/(sin(varphi__0)+1))^(1/2)*2^(1/2), (1/2)*2^(1/2)*(sin(varphi__0)+1)^(1/2))/C^(1/2)

(61)

 

 

Useful identities

FunctionAdvisor(identities, InverseJacobiSN)[3]

InverseJacobiSN(z, k) = InverseJacobiAM(arcsin(z), k)

(62)

InverseJacobiSN(z, k) = InverseJacobiAM(arcsin(z), k)

InverseJacobiSN(z, k) = EllipticF(z, k)

(63)

FunctionAdvisor(identities, InverseJacobiSN)[1]

JacobiSN(InverseJacobiSN(z, k), k) = z

(64)

FunctionAdvisor(identities, JacobiSN)[5]

JacobiSN(z, 1/k) = k*JacobiSN(z/k, k)

(65)

 

Explicit solution for `&varphi;__0`

Since Maple's solve does not solve (32) for `&varphi;__0`, one could try to isolate `&varphi;__0` in expression (32) by combining "somehow" the two elliptic expression into a single expression and to apply an inverse operation to it.

Maple's simplify or combine do not seem to be able to help in this respect. There might be addition theorems that could be applied but identifying them in Maple or in DLMF requires expertise in this field of special functions.

Easier is to try to evaluate (31) in different ways (see above) and hope for success. This yielded equivalent expressions with only one elliptic integral EllipticF.

Using identities such elliptic integrals can be converted to inverse elliptic functions where elliptic functions can be applied to. Trying this exemplarily for (61)  

 

L/sqrt(C) = InverseJacobiSN(sqrt(1-1/(sin(`&varphi;__0`)+1))*sqrt(2), (1/2)*sqrt(2)*sqrt(sin(`&varphi;__0`)+1))

L/C^(1/2) = InverseJacobiSN((1-1/(sin(varphi__0)+1))^(1/2)*2^(1/2), (1/2)*2^(1/2)*(sin(varphi__0)+1)^(1/2))

(66)

map(JacobiSN, L/C^(1/2) = InverseJacobiSN((1-1/(sin(varphi__0)+1))^(1/2)*2^(1/2), (1/2)*2^(1/2)*(sin(varphi__0)+1)^(1/2)), (1/2)*sqrt(2)*sqrt(sin(`&varphi;__0`)+1))

JacobiSN(L/C^(1/2), (1/2)*2^(1/2)*(sin(varphi__0)+1)^(1/2)) = (1-1/(sin(varphi__0)+1))^(1/2)*2^(1/2)

(67)

does not isolate `&varphi;__0`in the same way `&varphi;`(t)could be separated for the pendulum. The reason why such attempts are deemed to fail is simple. Differently to the pendulum, `#msub(mi("&varphi;",fontstyle = "normal"),mi("0"))` is not a constant "input" to the system but, causally speaking, an "output". While C in the case of the pendulum is constant and independent of `&varphi;__0`, C and `&varphi;__0`functionally depend on each other for the cantilever; i.e., `&varphi;__0` = `&varphi;__0`(C). This fundamentally makes the two cases different although many derivation steps are similar.

Student:-ODEs

Student:-ODEs:-ODESteps(diff(diff(varphi(t), t), t)+C*sin(varphi(t)) = 0)

Error, (in Student:-ODEs:-OdeSolveOrder2) ODE is not supported

 

Student:-ODEs:-ODESteps(diff(diff(varphi(s), s), s)+C*cos(varphi(s)) = 0)gives a solution for `&varphi;` = `&varphi;`(s)with two integration constants C1 and C2, but determining the integration constants with the first two boundary conditions of (12) is probably impossible. odetest confirms that the solution is correct but one of the arguments of an elliptic function is not unitfree (which raises more questions): JacobiSN((1/2)*sqrt(2*C-2*C1)*(-s+C2), sqrt(-(C1+C)/(-C1+C))).

Links

https://www.mapleprimes.com/questions/232863-Testing-Maples-Solution-Of-The-Nonlinear

https://www.mapleprimes.com/questions/131520-Animation-Of-A-Simple-Pendulum

 

Applying a horizontal load instead of a vertical bends the cantilever in an arc-like fashion. For this load case the corresponding ODE is that of the pendulum (see [2], chapter 5, exercise 8). The parametric equation (bending curve) of the arc becomes simpler but still no explicit solution `&varphi;__0` = `&varphi;__0`(C)seems possible.

Alternative symbols for 4

θ

phi, theta

References

[1] https://en.wikipedia.org/wiki/Pendulum_(mechanics)
[2] Lawden, Derek F. “Elliptic Functions and Applications.” Acta Applicandae Mathematica 24 (1989): 201-202.
[3] Bisshopp, K.E. and Drucker, D.C. (1945) Large Deflection of Cantilever Beams. Quarterly of Applied Mathematics, 3, 272-275.
[4] BELÉNDEZ, Tarsicio; NEIPP, Cristian; BELÉNDEZ, Augusto. "Large and small deflections of a cantilever beam". European Journal of Physics. Vol. 23, No. 3 (May 2002). ISSN 0143-0807, pp. 371-379
[5] Rouben Rostamian, https://www.mapleprimes.com/questions/236511-How-To-Integrate-This-Ode-And-How-To#answer295192
[6] Christian Wolinski, https://www.mapleprimes.com/questions/233304-How-To-Find-The-Inverse-Function-Of#comment283638

 

 

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Disability Pride Month happens every July to celebrate people with disabilities, combat the stigma surrounding disability, and to fight to create a world that is accessible to everyone. Celebrating disability pride isn’t necessarily about being happy about the additional difficulties caused by being disabled in an ableist society: as disabled blogger Ardra Shephard puts it, “Being proud to be disabled isn’t about liking my disability… [It] is a rejection of the notion that I should feel ashamed of my body or my disability. It’s a rejection of the idea that I am less able to contribute and participate in the world, that I take more than I give, that I have less inherent value and potential than the able-bodied Becky next to me.” The celebration started in the US to commemorate the passing of the Americans with Disabilities Act, which prohibits discrimination based on disability, and since then it has spread around the world.

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So what does any of this have to do with us here in the math community? Well, while it’s easy to think of mathematics as an objective field of study that contains no barriers, the institutions and tools used to teach math are not always so friendly. For an obvious example, if there's a few steps leading up to your math classroom and you use a wheelchair, that's going to be a challenge. And that's just scratching the surface—there are countless ways to be disabled, many of which are invisible, and many of which make a typical classroom environment very challenging to learn in for a variety of different reasons. As well, it can be difficult for prospective mathematicians to ask for accommodations, because of both the stigma against disability and the systemic barriers to receiving the proper accommodations. Just ask Daniel Reinholz, a disabled math professor at San Diego State University, whose health forced them to drop out of several engineering courses during their undergraduate degree: “Throughout it all, I never had a notion that I could receive accommodation or support, or that I deserved it. (Even though I’ve never really fit into the “right” category of disabled to be accommodated, so who knows what difference it really would have made.)” While Daniel was lucky enough to find a path to mathematics that worked for them, not all disabled people currently have that path available to them. As math professor Allison Miller puts it in her AMS blog post about disability in math, “Success in mathematics should not depend on whether someone’s needs happen to mesh sufficiently well with institutional structures and spaces that have been designed to serve only certain kinds of minds and bodies.”

While we can’t make systemic changes on our own, we here at Maplesoft can still do our part to make tools for math that are something everyone can use and enjoy. As such, we’re excited to share that Maple Learn is now compatible with the screen reader NVDA. By using this screen reader, and with our extensive keyboard shortcuts that negate the need for a mouse, individuals with low or no vision can now use Maple Learn to help them explore mathematics. All you need to do is select “Enable Accessibility” from the hamburger menu, and you’ll be ready to go! Maple Learn also includes the colour palette CVD, which is designed to be accessible to colourblind users. To learn how to access the colour palettes, check out this How-To document.

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There is still more work for us to be done to ensure that we’re doing our part to make math accessible to everyone. Not only are there still ways in which we’re working to improve the accessibility of our products, but we all as a math community need to strive towards recognizing the barriers we may have previously overlooked and finding ways to provide accommodation for all mathematicians. One organization, called Sines of Disability, is already working towards that very goal. They are a community of disabled mathematicians dedicated to dismantling the systemic ableism present in mathematics. For this Disability Pride Month, consider taking the time to check out these resources and learn more about this issue.

Can’t seem to find the mistake in your math? Instead of painfully combing through each line, let the new “Check my work” operation in Maple Learn help! Now in Maple Learn, you can type out a solution to a variety of math problems, and let Maple Learn check your work! Additionally, by signing on to Maple Learn and the Maple Calculator app, you can take a photo of your handwritten math, import it into Maple Learn, and check your work with the click of a button.

Whether you’re solving a system of linear equations or an algebra problem, computing an integral or a partial derivative, “Check my work” can help. Maple Learn will tell you which steps are “Ok” and which steps to double-check. If you get a step wrong, Maple Learn will point out which line has an error, then proceed to check whether the rest of your work followed the right procedure.

Here’s an example of a solution to a system of linear equations written out by hand. All I had to do was snap a picture in the Maple Calculator app, and Maple Learn instantly had my equation set ready to go in the Cloud Expressions menu. Then, I just clicked “Check my work” in the Context Panel.

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What happens if you make a mistake? Here’s an example of evaluating an improper integral with a u-substitution that involves a limit. This time, I directly typed my steps into Maple Learn and pressed “Check my work” in the Context Panel. Check my work recognized the substitution step and noted what step was incorrect; can’t forget to change the limits of integration! After pointing out where my mistake was, Maple Learn continued to evaluate the rest of my steps while taking my error into account. It confirmed that the rest of the process was correct, even though the answer wasn’t.

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What was established in 1788 in Prussia, is derived from the Latin word for “someone who is going to leave”, and can be prepared for using the many capabilities of Maple Learn? Why, it’s the Abitur exam! The Abitur is a qualification obtained by German high school students that serves as both a graduation certificate and a college entrance exam. The exam covers a variety of topics, including, of course, mathematics.

So how can students prepare for this exam? Well, like any exam, writing a previous year’s exam is always helpful. That’s exactly what Tom Rocks Math does in his latest video—although, with him being a math professor at Oxford University, I’d wager a guess that he’s not doing it as practice for taking the exam! Instead, with his video, you can follow along with how he tackles the problems, and see how the content of this particular exam differs from what is taught in other countries around the world.

Oh, but what’s this? On question 1 of the geometry section, Tom comes across a problem that leaves him stumped. It happens to the best of us, even university professors writing high school level exams. So what’s the next step?  Well, you could use the strategy Tom uses, which is to turn to Maple Learn. With this Maple Learn document, you can see how Maple Learn allows you to easily add a visualization of the problem right next to your work, making the problem much easier to wrap your head around. What’s more, you don’t have to worry about any arithmetic errors throwing your whole solution off—Maple Learn can take care of that part for you, so you can focus on understanding the solution! And that’s just what Tom does. In his video, after he leaves his attempt at the problem behind, he turns to this document to go over the full solution, making it easy for the viewer (and any potential test-takers!) to understand where he went wrong and how to better approach problems like that in the future.

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We’re now coming to the end of Pride Month, but that doesn’t mean it’s time to stop celebrating! In keeping with our celebration of queer mathematicians this month, we wanted to take some time to highlight the works of LGBT+ mathematicians throughout history. While it’s impossible to say how some of these individuals would have identified according to our modern labels, it’s still important to recognize that queer people have always existed, and have made and continue to make valuable contributions to the field of mathematics. It’s challenging to find records of LGBT+ people who lived in times when they would have been persecuted for being themselves, and because of that many contributions made by queer individuals have slipped through the cracks of history. So let’s take the time to highlight the works we can find, acknowledge the ones we can’t, and celebrate what the LGBT+ community has brought to the world of mathematics.

If you ask anyone to name a queer mathematician, chances are—well, chances are they won’t have an answer, because unfortunately the LGBT+ community is largely underrepresented in mathematics. But if they do have an answer, they’ll likely say Alan Turing. Turing (1912-1954) is widely considered the father of theoretical computer science, largely due to his invention of the Turing machine, which is a mathematical model that can implement any computer algorithm. So if you’re looking for an example of his work, look no further than the very device you’re using to read this! He also played a crucial role in decoding the Enigma machine in World War II, which was instrumental in the Allies’ victory. If you want to learn more about cryptography and how the field has evolved since Turing’s vital contributions, check out these Maple MathApps on Vigenère ciphers, password security, and RSA encryption. And as if that wasn’t enough, Turing also made important advances in the field of mathematical biology, and his work on morphogenesis remains a key theory in the field to this day. His mathematical model was confirmed using living vegetation just this year!

In 1952, Turing’s house was burgled, and in the course of the investigation he acknowledged having a relationship with another man. This led to both men being charged with “gross indecency”, and Turing was forced to undergo chemical castration. He was also barred from continuing his work in cryptography with the British government, and denied entry to the United States. He died in 1954, from what was at the time deemed a suicide by cyanide poisoning, although there is also evidence to suggest his death may have been accidental. Either way, it’s clear that Turing was treated unjustly. It’s an undeniable tragedy that a man whose work had such a significant impact on the modern era was treated as a criminal in his own time just because of who he loved.

An image of Alan Turing next to a diagram of a Turing machine computing the busy beaver problem.

Antonia J. Jones (1943-2010) was a mathematician and computer scientist. She worked at a variety of universities, including as a Professor of Evolutionary and Neural Computing at Cardiff University, and lived in a farmhouse with her partner Barbara Quinn. Along with her work with computers and number theory, she also wrote the textbook Game Theory: Mathematical Models of Conflict. If you want to learn more about that field, check out this collection of Maple Learn documents on game theory. As a child, Jones contracted polio and lost the use of both of her legs. This created a barrier to her work with computers, as early computers were inaccessible to individuals with physical disabilities. Luckily, as the technology developed and became more accessible, she was able to make more contributions to the field of computing. And that’s especially lucky for banks who like having their money be secure—she then exposed several significant security flaws at HSBC! That just goes to show you the importance of making mathematics accessible to everyone—who knows how many banks’ security flaws aren’t being exposed because the people who could find them are being stopped by barriers to accessibility?

An image of Antonia J. Jones next to the cover of the textbook she wrote: Game Theory: Mathematical models of conflict.

James Stewart (1941-2014) was a gay Canadian mathematician best known for his series of calculus textbooks—yes, those calculus textbooks, the Stewart Calculus series. I’m a 7th edition alumni myself, but I have to admit the 8th edition has the cooler cover. To give you a sense of his work, here’s an example of an optimization problem that could have come straight from the pages of Stewart Calculus. Questions just like this have occupied the evenings of high school and university students for over 25 years. I suspect not all of those students really appreciate that achievement, but nonetheless his works have certainly made an impact! Stewart was also a violinist in the Hamilton Philharmonic Orchestra, and got involved in LGBT+ activism. In the early 1970s, a time where acceptance for LGBT+ people was not particularly widespread (to put it lightly), he brought gay rights activist George Hislop to speak at McMaster University. Stewart is also known for the Integral House, which he commissioned and had built in Toronto. Some may find the interior of the house a little familiar—it was used to film the home of Vulcan ambassador Sarek in Star Trek: Discovery!

An image of James Stewart next to the cover of the 8th edition Stewart Calculus textbook.

Agnes E. Wells (1876-1959) was a professor of mathematics and astronomy at Indiana University. She wrote her dissertation on the relative proper motions and radial velocities of stars, which you can learn more about from this document on the speed of orbiting bodies and this document on linear and angular speed conversions. Wells was also a woman’s rights activist, and served as the chair of the National Woman’s Party. In her activism, she argued that the idea of women “belonging in the home” overlooked unmarried women who needed to earn a living—and women like her who lived with another woman as their partner, although she didn’t mention that part. There is a long-standing prejudice against women in mathematics, and it’s the work of women like Wells that has helped our gradual progress towards eliminating that prejudice. To be a queer woman on top of that only added more barriers to Wells’ career, and by overcoming them, she helped pave the way for all queer women in math.

An image of Agnes E. Wells next to a table from her dissertation on the movement of stars.

Now, there is a fair amount of debate as to whether or not our next mathematician really was LGBT+, but there is sufficient possibility that it’s worth giving Sir Isaac Newton a mention. Newton (1642-1727) is most known for his formulation of the laws of gravity, his invention of calculus (contended as it is), his work on optics and colour, the binomial theorem, his law of temperature change… I could keep going; the list goes on and on. It’s unquestionable that he had a significant impact on the field of mathematics, and on several other fields of study to boot. While we can’t know how Newton may have identified with any of our modern labels, we do know that he never married, nor “had any commerce with women”[a], leading some to believe he may have been asexual. He also had a close relationship with mathematician Nicolas Fatio de Duillier, which some believe may have been romantic in nature. In the end, we can never say for sure, but it’s worth acknowledging the possibility. After all, now that more and more members of the LGBT+ community are feeling safe enough to tell the world who they are, we’re getting a better sense of just how many people throughout history were forced to hide. Maybe Newton was one of them. Or maybe he wasn’t, but maybe there’s a dozen other mathematicians who were and hid it so well we’ll never find out. In the end, what matters more is that queer mathematicians can see themselves in someone like Newton, and we don’t need historical certainty for that.

An image of Isaac Newton next to a Maple Learn document depicting how light passing through a prisim becomes a rainbow.

So there you have it! Of course, this is by no means a comprehensive list, and it’s important to recognize who’s missing from it—for example, this list doesn’t include any people of colour, or any transgender people. Sadly, because of the historical prejudices and modern biases against these groups, they often face greater barriers to entry into the field of mathematics, and their contributions are frequently buried. It’s up to us in the math community to recognize these contributions and, by doing so, ensure that everyone feels like they can be included in the study of mathematics.

Some texts distinguish between unary and binary negation signs, using short dashes for unary negation and a longer dash for binary subtraction. How important is this distinction to users of Maple?

Some earlier versions of Maple used to have short dashes for negation (in some places). Maple 2023 has apparently abandoned the short dash for unary negation, and all such signs are now a long dash.

How about math books? Do all texts make this short-long distinction? The typesetters for my 2001 Advanced Engineering Math book also opted for all long dashes and that book was set from the LaTeX exported from Maple 20+ years ago. But I also have texts in my library that use a short dash for unary negation, on the grounds that -a, the additive inverse of "a" is a complete symbol unto itself, the short dash being part of the symbol for that additive inverse.

Apparently, this issue bugs me. Am I making a tempest in a teapot?

We are happy to announce another Maple Conference this year, to be held October 26 and 27, 2023!

It will be a free virtual event again this year, and it will be an excellent opportunity to meet other members of the Maple community and get the latest news about our products. More importantly, it's a chance for you to share the work work you've been doing with Maple and Maple Learn. There are two ways to do this.

First, we have just opened the Call for Participation. We are inviting submissions of presentation proposals on a range of topics related to Maple, including Maple in education, algorithms and software, and applications. We also encourage submission of proposals related to Maple Learn. 

You can find more information about the themes of the conference and how to submit a presentation proposal at the Call for Participation page. Applications are due July 11, 2023.

Presenters will have the option to submit papers and articles to a special Maple Conference issue of the Maple Transactions journal after the conference.

The second way in which to share your work is through our Maple Art Gallery and Creative Works Showcase. Details on how to submit your work, due September 14, 2023, are given on the Web page.

Registration for attending the conference will open later this month. Watch for further announcements in the coming weeks.

I encourage all of you here in the Maple Primes community to consider joining us for this event, whether as a presenter or attendee!

Paulina Chin
Contributed Program Chair

Probability distributions can be used to predict many things in life: how likely you are to wait more than 15 minutes at a bus stop, the probability that a certain number of credit card transactions are fraudulent, how likely it is for your favorite sports team to win at least three games in a row, and many more. 

Different situations call for different probability distributions. For instance, probability distributions can be divided into two main categories – those defined by discrete random variables and those defined by continuous random variables. Discrete probability distributions describe random variables that can only take on countable numbers of values, while continuous probability distributions are for random variables that take values from continuums, such as the real number line.

Maple Learn’s Probability Distributions section provides introductions, examples, and simulations for a variety of discrete and continuous probability distributions and how they can be used in real life. 

One of the distributions highlighted in Maple Learn’s Example Gallery is the binomial distribution. The binomial distribution is a discrete probability distribution that models the number of n Bernoulli trials that will end in a success.

This distribution is used in many real-life scenarios, including the fraudulent credit card transactions scenario mentioned earlier. All the information needed to apply this distribution is the number of trials, n, and the probability of success, p. A common usage of the binomial distribution is to find the probability that, for a recently produced batch of products, the number that are defective crosses a certain threshold; if the probability of having too many defective products is high enough, a company may decide to test each product individually rather than spot-checking, or they may decide to toss the entire batch altogether.

An interesting feature of the binomial distribution is that it can be approximated using a different type of distribution. If the number of trials, n, is large enough and the probability of success, p, is small enough, a Poisson Approximation to the Binomial Distribution can be applied to avoid potentially complex calculations. 

To see some binomial distribution calculations in action and how accurate the probabilities supplied by the distribution are, try out the Binomial Distribution Simulation document and see how the Law of Large Numbers relates to your results. 

You can also try your hand at some Binomial Distribution Example Problems to see some realistic examples and calculations.

Visit the Binomial Distribution: Overview document for a more in-depth explanation of the distribution. The aforementioned Probability Distributions section also contains overviews for the geometric distribution, Poisson distribution, exponential distribution, and several others you may find interesting!

2-dimensional motion and displacement are some of the first topics that high school students learn in their physics class. In my physics classes, I loved solving 2-dimensional displacement problems because they require the use of so many different math concepts: trigonometry, coordinate conversions, and vector operations are all necessary to solve these problems. Though displacement problems can seem complicated, they are easy to visualize.
For example, below is a visualization of the displacement of someone who walked 10m in the direction 30o North of East, then walked 15m in the direction 45o South of East:

From just looking at the diagram, most people could identify that the final position is some angle Southeast of the initial position and perhaps estimate the distance between these two positions. However, finding an exact solution requires various computations, which are all outlined in the Directional Displacement Example Problem document on Maple Learn.

Solving a problem like this is a great way to practice solving triangles, adding vectors, computing vector norms, and converting points to and from polar form. If you want to practice these math skills, try out Maple Learn’s Directional Displacement Quiz; this document randomly generates displacement questions for you to solve. Have fun practicing!

 

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