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So suppose in one maple worksheet, I run:

>assume(w, real); y:=2*w;
>save y, "test.m";

And then I open another, and run

>read "test.m";

The substitution won't work, while it works if I don't make any assumptions about the variable w.  However, in the piece of code I'm actually running (this snippet is just to illustrate the problem), I need to make the assumption that w is real for solving a system of equations (otherwise maple seems to run out of memory).  Is there a way to save my result y in such a way so that I can make substitutions for w later?

Hi everyone,

I wanted to plot the fourier series up to a given order of a step function using the code I attached, to change the order I used a sum with upper boundary M. When setting M to a particular value and plotting the function the result is obtained within a second, when on the otherhand using plot(subs(M=11,...),...) it takes close to a minute to produce a picture.

This might be a misuse of subs, in any case, I wanted to share my experience and maybe get an explanation about why this takes that much longer.




f := proc (t) options operator, arrow; sum(-4*sin((2*n+1)*t)/(Pi*(2*n+1)), n = 0 .. M) end proc

proc (t) options operator, arrow; sum(-4*sin((2*n+1)*t)/(Pi*(2*n+1)), n = 0 .. M) end proc


plot(subs(M = 11, f(t)), t = 0 .. 2*Pi)


M := 11; plot(f(t), t = 0 .. 2*Pi)



I wish to substitute Re=W[0]/V[0] in the expression V[0]/W[0] * diff(u(t),t). I tried using the subs command but it didn't work. Any help would be appreciated !


Why do the first two of the following 4 examples not work in Maple 15?

subs(m=21,`mod`(m, 4));
subs(m=21,m mod(4));
`mod`(21, 4);
21 mod(4);

Is there a (simple) workaround?


Dear all,

I would like to solve the Fredholm Integral equation, using numerical method.
This is my code.

there is a problem with subs, does not working here.
# Then, we obtain from (9) the coeficient A[n] and B[n].

Then I woulk like to recompute (2), and then compute (1).
# Puting x=m*h, in (1), how can we generate a linear Matrix from (1).


I want to find the solution in a special form.
How can I do it?
Here is what I tried:



In the left hand side u_1 is not changed in  D(u_1).
I want to substitute and evalute (differentiate) it.

Thanks,  Sandor





Hi everybody,

Suppose that in an equation, I have the term x/(t).  I want to substitute it by v(t).  Any suggestion because I am trying but don't find an help page on this.


Thank you in advance for your help!


Mario Lemelin
Maple 17.01 Ubuntu 13.10 - 64 bits
Maple 17 Win 7 - 64 bits messagerie : téléphone :  (819) 376-0987

Hello, I have different values to substitute into my theta in a matrix. I tried to use the subs function but the results came out are all dashes. Have you any idea how to fix it please?


I tried method 1:


Method 2:

for m from 1 to 3 do
for n from 1 to 5 do
end do:
end do:

Thank you.

The following integral is solved easily via a substitution. Why does Maple not evaluate it?

int(tan(x)^(1/3)*sec(x)^2, x)

int(tan(x)^(1/3)*sec(x)^2, x)


int(surd(tan(x), 3)*sec(x)^2, x)

int(surd(tan(x), 3)*sec(x)^2, x)





I have a differential equation:

an the solution:

I want to substitute

ekf := omega = sqrt(c/m);

algsubs(ekf, sol);
but sol does not change.

This works a bit but does not substitute everything in a way that you would expedect

This is the result:

Thanks in advance

I was doing some practice problems for Maple, when I encountered this problem:


My code is





The output however did not change both `x+2`'s into `u`.


The output was: x+2+sin(u)


Any ideas as to why? Thanks in advance.


The subs command is not working properly for Vector type, see worksheet.

I can use simplify instead, but that's not what I really wanted.




Hi all,

I am having some problems when solving high order polynomials. When oders are 'high' and systems involve multiple variables, Maple is slow to do so.

See in worksheet for detailed codes.

kappa - gives the vector that i am interested in

sC - a reparameterisation which has 'summation' in it

Aim is to verify that it works (it should!)

I currently ask...


Say for a 126 by 18 symbolic matrix, substituting numerical values into the matrix DD1 takes about 10 seconds (using time() );

for a 62 by 16 matrix, take just about 1/5 second.

By when the matrix is about 254 by 20, it take much longer! More than a minute!

I never actually waited how long, but I am wondering if there is something wrong? Am I using the right command?

Say the matrix is DD1 with numpar:=[x=0.3,y=0.2,z=0.98,....]

I'm using Maple to come up with equations, and then I'm substituting in variable names for functions which I can then output to Matlab.

I haven't had any problems until I ran into partial derivates described by the D[] operator.  For example, if i have a function f described by f(x(t),y(t)) and I differentiate it wrt t, I get 

D[1](f)(x(t),y(t))*(x(t)_dot) + D[2](f)(x(t),y(t))*(y(t)_dot)

I want to make a substitution for D[1](f)(x(t),y(t)) and D[2...

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