Maple 2020 Questions and Posts

These are Posts and Questions associated with the product, Maple 2020

This worksheet displays an intersection between two spheres based on a test which seems unrelated to the display.

How can this be explained?


This chunk of code gives me almost instantly the desired result with Maple 2015 but fails returning a result after 5 minutes when ran from  Maple 2020.
Changing the method or trying to tune their options doesn't fix the issue (for a larger value of the absolute tolerance the result, close to 1, is even obviously false).

Could you please help me to fix this?



`Standard Worksheet Interface, Maple 2015.2, Mac OS X, December 21 2015 Build ID 1097895`



Model_1 := (X, Y, Z) -> 1.3479120558270161+(-1)*.3390713110446567*X+1.0332964944900824*Y+(-1)*.8046331250569234*Z+0.9028899142595827e-1*X^2+(-1)*.28022910356641223*Y^2+1.3698461513469624*Z^2+0.6023630210658247e-1*Y*X+(-1)*.1988111077193626*Z*X+.6782902277463169*Z*Y+(-1)*0.7589729001497135e-1*X*Y*Z:

Model_2 := (X, Y, Z) -> .7215754021067852-.961682838202105*X+.4890842364596477*Y-.8214961524335734*Z+.15745942215497866*X^2-1.8023544416693338*Y^2+.36598799463016246*Z^2+1.3957614823018496*Y*X+.725398415577742*Z*X+1.9474707393604542*Z*Y-1.1780201448596594*X*Y*Z:

ExpMod_2 := unapply(expand(Model_2(Model_1(X1, Y1, Z1), Y2, Z2)), (X1, Y1, Z1, Y2, Z2)):

fy1 := PDF(Normal(0.1055, 0.0297), Y1):
fz1 := PDF(Normal(1, 0.2/3), Z1):
fy2 := PDF(Normal(0.17, 0.0476), Y2):
fz2 := PDF(Normal(1, 0.2/3), Z2):

C   := evalf(
         (1-eval(CDF(Normal(0.1055, 0.0297), Y), Y=0))
         (1-eval(CDF(Normal(0.17, 0.0476), Y), Y=0))
         (eval(CDF(Normal(1, 0.2/3), Z), Z=1.2)-eval(CDF(Normal(1, 0.2/3), Z), Z=0.8))^2

J  := Int(
        fy1*fz1*fy2*fz2*(1+tanh(10^4*(ExpMod_2(2.14, Y1, Z1, Y2, Z2)-1.25)))/2,
        method = _CubaDivonne, methodoptions=[absepsilon=1e-8]

Prob(X__2 > 1.25) = nprintf("%1.3e", evalf(J)/C);

Prob(1.25 < X__2) = `8.462e-08`




When trying to print a Maple Document as a PDF on Mac, I am now getting an "Error while printing" message. A 1-page pdf is created that's empty.   This is a new error, one that I've never seen when printing as PDF for any other Maple Document I've created.

I'm running Mac OS 12.3.1, the latest version of Mac OS and using Maple 2020.

I'm trying to solve a coupled inductor problem.  All I'm trying to do is solve for the currents (which I could do), then solve for resonance by setting the imaginary part of I1 to 0 and solving for omega.  I then want to plug this resonant frequency back into I1 and evaluate it for some component values and coupling coefficient.

The problem is that even though I define the various variables as real,  Maple doesn't seem to recognize them as such.  I suspect I've failed to define one of them, and that is why it is responding like it is, but I can't find it.  

I'm also getting some weird behavior.....for example if I type :  wres0, I get the value I assigned to it --that's fine.  But then, when I type : wres0/(2*pi), I get an error, "Error, unable to parse 'mverbatim"   --- what does this mean?

This should be a pretty straight forward calculation on Maple, but at this point, I think I may be better off doing it by hand!  I appreciate any help you can provide.  Thank you.

This worksheet animates part of the motion of the classic ladder sliding down a wall.

Please answer the two questions posed in the opening text.

Respondents will need to establish their own link to the DirectSearch package

Hello all, 

Would you allow me to ask this one question?
[moderator: See also this previous question]

Is there any possible way to treat the differentiation operator (e.g., 'D') as an ordinary coefficient of a polynomial?

For example, as described in the attached worksheet, I was wondering if there is a way to re-write the LHS of the expression 'eq_e5_9b' as the expression 'desired'. 

In Kwon Park 



eq_e5_9b := psi__d0*Delta__delta(t) + psi__q0 * D(Delta__delta(t))/omega__0 = p_(Delta__psi__d(t))/omega__0 - Delta__psi__q(t);

psi__d0*Delta__delta(t)+psi__q0*D(Delta__delta(t))/omega__0 = p_(Delta__psi__d(t))/omega__0-Delta__psi__q(t)


collect(lhs(eq_e5_9b), Delta__delta(t));



desired := Delta__delta(t) * (psi__d0 + psi__q0 * D/omega__0);





I am trying to decide O of times fo a computer process. I thought it was n^2*log(N) or something like that.

With 12  points, it may be hard to determine if O(N^4), etc.


The uploaded worksheet attempts to determine arc lengths of an ellipse by two methods. Why do their results differ?

I want to integrate the function int(1/(A^2 - B^2*cos(t))^(1/2), t = 0 .. 2*Pi), I get the correct solution, but I want to prevent all the "if" statements from appearing. I have tried to use "assume" but the if statement still does not disappear.  


Is there any way to save "explore plot" in such a way that the slider of constants should appear in the extension file?

So that I can see the constant changing in the extension file too.

For example for an ellipsoid with principal axes 3, 2 and 1 along the x, y and z coordinate axes respectively, with center at the origin and truncated at x equals 1.

What math will reveal its center of mass and its moment of inertia for an axis of revolution through the center of mass and parallel to the y axis?


I wanted to know how to search a list of permutations given criteria: print the permutation(s) If the 4th element of each perm was equal to [C,Z} and the seventh was equal to [B,Y]

I tried to simplify this equation:

where Ts,Cf,Rf,Lg & L are Variables to equivelent equation in the form of:

                                                         (.....)Z3+(....)Z2+(.....)Z+(.........)      /   (.....)Z3+(....)Z2+(.....)Z+(.........)

Hi professors,

Please can someone help me 
i want code of  function in maple to calculate values  of B(t), 

i have this matlab code

T = 1; N = 5; dt = T/N;

dW = sqrt(dt)*randn(1,N);   
W = cumsum(dW)

but does not calculate B(0.25) and B(0.5)



Say I have 3 players on 2 teams. The teams play each other and there are 9 single [[A[s], B[s]], [A[s], B[m]], [A[s], B[w]], [A[m], B[s]], [A[m], B[m]], [A[m], B[w]], [A[w], B[s]], [A[w], B[m]], [A[w], B[w]]]matchups.

A, B, C & X, Y, Z. are the players. A and X are the strongest players, C and Z are the weakest.

Here's one: [[A,X],[B,Y],[C,Z],[A,Y],[B,Z],[C,X],[A,Z],[B,X],[C,Y]]

So i'm looking for some code to display all such permutations.

Carl came up with some code a while back which 'kind of' does it

P:= [A,B]:  S:= [s,m,w]:
[seq(rtable((1..nops(S)) $ nops(P), ()-> index~(P, S[[args]]), order= C_order))];
[[A[s], B[s]], [A[s], B[m]], [A[s], B[w]], [A[m], B[s]], [A[m], B[m]], [A[m], B[w]], [A[w], B[s]], [A[w], B[m]], [A[w], B[w]]]

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