I am trying to use "solve" to solve a set of 2 equations defined by using summation function "sum". But I got an error saying "Error, (in sum) summation variable previously assigned, second argument evaluates to 3 = 1 .. 2". 

The Maple code is listed here

restart;
N := 2:
var:= seq(alpha[n], n = 1 .. N):
v(x):=sum(alpha[n]*phi[n](x), n = 1 .. N):
R(x):=diff(v(x), x $ 4) - p/EI:
eqs := seq('int'('R(x)'*phi[n](x), x = 0 .. L) = 0, n = 1 .. N):
for n to N do
    phi[n](x):= sin((2*n - 1)*Pi*x/L):
end do:       
solve({eqs}, {var});
Error, (in sum) summation variable previously assigned, second argument evaluates to 3 = 1 .. 2

current_mirror.msim

I try to simulate a current mirror model, but it doesn't work and say "cannot evaluate the solution past the initial point, problem may be complex, initially singular or improperly set up". Maybe some incorrect parameters are set there, could you fix it? 

Hi,

While playing with this, I got:

> sum(Beta(k,1/2)/(2*k+1)^2,k=1..infinity)
Error, (in SumTools:-DefiniteSum:-ClosedForm) summand is singular in the interval of summation

I don't see how this can be singular, as Beta(k,1/2) is trivially bounded for k>=1, and sum(1/(2*k+1)^2) is absolutely convergent.

Maple is still able to evaluate numerically the inert sum (I get 0.3361376233). If I replace Beta with the expression with GAMMA, I get a result with MeijerG, that doesn't seem to help much for numerical evaluation, as it takes a long time and gives the wrong result -1.966769953*10^10 - (6.886827095*10^8)*I.

I have no reason to expect a closed form for this sum, but the error is surprising. And I don't know MeijerG well enough to explain the numerical error either. It fails with Maple 2020, 2021 and 2022.

Hi,

I try to animate the tangent in a moving point on the curve

ideas ?

Thanks

QuestionAnim.mw

Hey, I've got simmilar problem. I will show it on the same example, but here my expressions are defined as functions and both graphs should be on the same plot. With my version I get:

Warning, expecting only range variable x in expression a*x^2 to be plotted but found name a

My version is:

;

Version below works fine, but I wanted to have this plot in a worksheet not in popup window:

Thanks in advance,

Iza

I try to simplify the expression by putting exponential function into equation but the maple shows error which I can't fix it.simplification.mw

Hi,

I am trying to use Maple to solve a PDE involving composite functions.  How do I program this?  Here is an attached file describing what I am trying to do.

Partial_Differential_Equations_of_Composite_Functions.mw

Hi I was trying to difine a constant c that exists in range(0,d). The constant c has two values and is depends on its x location.  The first value "a"  has a duration "e" , the second value "b" has a duiration "f". Start from x =0, the constant c has value "a", then "b", then "a"......

 How should I define this constant in "piecewise"?

In a multibody assembly I have three instances of identically connected prismatic joints (flanges not conneted and identical componets at the frames)

In the simulation results the joints are listed with the following variables:

Why are the variables not the same for three identical components and what do the Fi and Mi stand for?

Is there any documentation on variables listed in the simulation results? It seems that more variables can be available than listed in the component documentation.

I have the following example.

> A:= Vector(3,symbol=v)

A:= 

>v[1]:= 5

v[1]:=5

> A

Is there any way such that v[1] is actually referring to the first element in the vector? In other words, changing v[1] actually modifies the vector A.

If the question does not make sense, then here is the actual scenario that I faced.

I need to solve a system of equations in the form of 

where a[i], c[i] refers to the entries in the vector.

solve returns the following:

I then did an assign(%). However, the entries in A and C are not changed. I want the answer returned by solve to be properly applied to the entries of the vectors.

I have been trying to integrate the following an expression using Maple's command PathInt:

PathInt(4*x*y*(y^4+2*x*y-2)/sqrt((1-(2*x*y)^2+(-3*y^2+1)^2)*(1+(y^2-1)^2)), [x, y] = Path(`<,>`(-(1+sqrt(2))*cos(t)-(sqrt(2)-1)*sin(t), cos(t)-sin(t)), t = 0 .. 2*Pi)).

However, Maple does not return a result, but rather an integral. Is there an alternative way to solve the integral above?

Thanks in advance.

However, I wish my b(x) to be x^2 + x + 1. How could I do it?

 I have the following code snippet.

It is surprising to me that using a package actually changes the behaviour of functions not in the package!

Is this a bug or a feature that I am not aware of?

Hi I am trying to plot in maple but the plot I get is not the one I expect I have attached the maple file and the expected image below. Any help would be appreciated.