Hi,

    i meet  a partial differential equation seems not complicated

with(PDEtools):

PDE := (diff(f(x__1, x__2, p__1, p__2), x__1))*p__1/m-(diff(f(x__1, x__2, p__1, p__2), p__1))*(2*k*x__1-k*x__2)+(diff(f(x__1, x__2, p__1, p__2), x__2))*p__2/m-(diff(f(x__1, x__2, p__1, p__2), p__2))*(-k*x__1+2*k*x__2);

when i use

     pdsolve(PDE);

i get nothing,but i sure

    f=c*(p__1^2/m+p__2^2/m+4*p__1*p__2/m+6*k*x__1*x__2) 

is the one solution of the differential equation .

how i can get solutions about of the above equation.

thanks .

I am wondering if Selection Statement 'if' can be coded in Embedded Components such as Text Area.

I have typed codes in the Text Area(%text_beta_degress) as follows:

if %text_beta_degress=1.2 then Do(%text_ps=28);Do(%text_l4=5.439);
elif %text_beta_degress=8.77 then Do(%text_ps=15);Do(%text_l4=2.785);
elif %text_beta_degress=10 then Do(%text_ps=12.83);Do(%text_l4=2.348);
elif %text_beta_degress=14.4 then Do(%text_ps=5);Do(%text_l4=0.758);
end if

When I typed 1.2 or 8.77 into the Text Area(%text_beta_degress) and tapped 'Enter', %text_ps and %text_l4 didn't response.

Is there any solution?

How can I solve the following system in Maple for $S_1$ and $S_{i+1}$? I have the code written, but it is giving me nothing as output.

eq1 := Q-A*S[1]*C/X+B*D*(sum(S[j], j = 2 .. i+1))/Y-r[1]*S[1] = 0;
eq2 := A*S[i-1]*C/X-A*S[i]*C/X-B*S[i]*D/Y-r[1]*S[i] = 0;
eq3 := A*S[i]*C/X-B*S[i+1]*D/(Y+S[i+1])-r[2]*S[i+1] = 0;
solve({eq1, eq2, eq3}, {S[1], S[i+1]});

The only non-constants in the system are the $S_j$'s for $j = 1, \ldots, i+1$.

Here is the system in math mode:
$$Q-\frac{AC}{X}S_1-r_1 S_1 +\frac{BD}{Y}\sum\limits_{j=2}^{i+1}S_j = 0 \\
\frac{AC}{X}S_{i-1} - \frac{AC}{X}S_i - \frac{BD}{Y}S_i - r_1 S_i = 0\\
\frac{AC}{X}S_i - \frac{BD S_{i+1}}{Y+S_{i+1}} - r_2 S_{i+1} = 0 $$

I have a head start on it by hand, but it's too cumbersome to complete.

Basically, my strategy is to solve for $S_{i+1}$ as a function of $S_1$ and some constants. Then to plug in $S_2, \ldots, S_{i+1}$ in the summation and solve for $S_1$ as a function of constants. Then I would obtain $S_{i+1}$ as a function of constants itself.

Thanks for any help.

I'm trying to solve the differential equation.

Eq := diff(y(x), x, x) = -(x^2+1)*y(x)+K;

dsolve({Eq, y(-1) = 0, y(1) = 0}, y(x));

But this not work very well.

Best Regards,

I related two Text Area Components by using the codes "Do(%text_beta_radian=evalf(%text_beta_degress/180*Pi))".

I wanna know what codes can refresh the display of the text area component with name%text_beta_radian

after I change the input value of that%text_beta_degress?

that can run without maple using my own maple code?

And how about Maplesim? I heard that Maplesim can generate executable file

I want to solve an ODE from Game Theory, the Cournot competition.

It says

p(q1+r2(q1))+p'(q1+r2(q1))*r2(q1)-c2'(r2(q1))=0

 where, I think,

' means diff(,q1),

c2(q2)=c*q2 for a fixed c in [0,1]

and

p(q)=max(0,1-q).

So c2,p and r2 are functions.r2 goes from [0,inf) to [0,inf).

I look for r2, which should be r2(q1)=(1-q1-c)/2 when correctly solved.

However, the command dsolve says Error in dsolve (divison by 0).

 What is wrong? How do I obtain the solution for r2 in Maple?

Hello,

I am trying to differentiate a matrix containing four variables, alpha, alphaB (representing alpha bar), beta, and betaB (for beta bar). They are are variables with respect to t. I then need to let t=0 and then simplify the result with some initial conitions i have. Could you tell me any useful maple functions which i can use to do this? If you need anymore information let me know and thank you for helping me.

Robbie

restart;

with(DETools, diff_table);

kB := 0.138064852e-22;

R := 287.058;

T := 293;

p := 101325;

rho := 0.1e-2*p/(R*T);

vr := diff_table(v_r(r, z));

vz := diff_table(v_z(r, z));

eq_r := 0 = 0;

eq_p := (vr[z]-vz[r])*vr[] = (vr[]*(vr[r, z]-vz[r, r])+vz[]*(vr[z, z]-vz[z, r]))*r;

eq_z := 0 = 0;

eq_m := r*vr[r]+r*vz[z]+vr[] = 0;

pde := {eq_m, eq_p};

IBC := {v_r(1, z) = 0, v_r(r, 0) = 0, v_z(1, z) = 0, v_z(r, 0) = r^2-1};

sol := pdsolve(pde, IBC, numeric, time = z, range = 0 .. 1);

what am I doing wrong?

it's telling me: Error, (in pdsolve/numeric/par_hyp) Incorrect number of boundary conditions, expected 3, got 2
but i did just as in the example :-/

Hello,

I tried to solve below equation, but it gives me zeros result. Please help me to find their inverse laplace. 

 It will be clearer if was pasted on Maple:

restart

Ps := [P[0], P[1], P[2], P[3], P[4]]:

eqs := [P[0](s) =~ (P[1](s)*mu[1]+P[2](s)*mu[2]+P[3](s)*mu[3]+P[4](s)*mu[4])/(s+lambda[1]+lambda[2]+lambda[3]+lambda[4]), P[1](s) = lambda[1]*P[0](s)/(s+mu[1]), P[2](s) = lambda[2]*P[0](s)/(s+mu[2]), P[3](s) = lambda[3]*P[0](s)/(s+mu[3]), P[4](s) = lambda[4]*P[0](s)/(s+mu[4])];

Ls := solve(eqs, Ps(s))[];

P(t)=~inttrans[invlaplace]~(rhs~(Ls), s, t);

Thank you

How do I make maple to show the values of my variables in my calculation automatically? I want it to look somewhat like this:

https://gyazo.com/df9fe1193091fb771ff99d6187c9195f

Instead of this:

https://gyazo.com/936894920a6cb89082fb94d66f8e4291

Hello

I have a complex set of Markov Processes in reliability application. To make them simpler for me, as a beginner in Maplesoft, I solve them manually to reach a point where I need inverse Laplace for a set of equations. For illustration, I used a simple example below. If I get the concepts for below example, I can apply them on more complicated systems, as following:

P₀(s) = 1/(s+λ)+υ*P₁(s)/(s+λ)

P₁(s)=γ*P₀(s)/(s+υ)

Mannuly I find that:

P₀(t)=υ/(s+λ)+λ*exp(-(λ+υ)t)/(υ+λ)

P₁(t)=υ/(s+λ)-λ*exp(-(λ+υ)t)/(υ+λ)

Please help me step by step to understand how to solve such inverse Laplace. 

Thank you,

Hi,

     I have a list of 603 integrals that I want to evaluate. Unfortunately, I can't get Maple to do most of them. Mathematica can do some that Maple can't, and returns an answer in terms of BesselJ functions. So my question is 2-fold

1) Is there a way to make Maple do this integral?
2) If not, is there a way to efficiently convert 603 expessions to Mathematica and back?

EXAMPLE INTEGRAL
restart;
assume(k1::real, k2::real, R::real, R>0);
a :=cos(x)*exp(I*(k1*R*sin(x)+k2*R*sin(x)-4*x))*sin(x):
int(a, x=-Pi/2..Pi/2) assuming real;


Thanks! 

Download ToughIntegral.mw

Hello,
I have defined a function f (x, e, y).  I give values of n: = i * h as follows:

f (x (n), w (n), t) = w * t * x;
n: = i * h;
r (n) = n;
Then I need to do this operation:
w (n) = w (n) + r (n);

w(n):=15; r(n):=30;

w(n):=w(n)+r(n);

w(n);
Error, (in w) too many levels of recursion.

How i can operate?.

Regards.

Wonder if this can be accomplished in Maple.

so I have a list of 100 items labeled {1..100} of various value {$100, $160, $220, ......  , }

the task is to distribute these items among 3 people A,B,C so they get an approximately equal share.

Adding the values and dividing by 3 gives the dollar total to aim for. 

This post has C.Love procedure for evenly sized groups

 http://www.mapleprimes.com/questions/200480-Product-Grouping

but what i want is a method for different sized groups. ie 25 items for A, 35 for B and 40 for C (user defined).

additionally there is a fixed constraint: A has been bequeathed items 1,4,8; B items 2 and 20; C item 50.

restart:
S:= {3, 4, 5, 6, 8, 9, 28, 30, 35}:
SL:= [A,B,C,D,E,F,G,H,I]:
assign(Labels ~ (S) =~ SL); #Create remember table.
AllP:= [seq(P, P= Iterator:-SetPartitions(S, [[3,3]], compile= false))]:
lnp:= evalf(ln((`*`(S[]))^(1/3))):

Var:= proc(P::({list,set}(set)))
local r:= evalf(`+`(map(b-> abs(ln(`*`(b[]))-lnp), P)[]));
end proc:

Min:= proc(S::{list,set}, P::procedure)
local M:= infinity, X:= (), x, v;
     for x in S do
          v:= P(x);
          if v < M then  M:= v;  X:= x  end if
     end do;
     X
end proc:

ans:= Min(AllP, Var);
              [{3, 9, 35}, {4, 8, 28}, {5, 6, 30}]
subsindets(ans, posint, Labels);
               [{I, A, F}, {B, E, G}, {C, D, H}]