## 509 Reputation

12 years, 115 days

## Convert Sum to Matrix form...

Maple 14

Hi all,

I have this two equations:

ap[k]=Sum(a[n]*sin(n*theta)*f(n,k),n=1..nn);

a[n]=Sum(ap[k]*g(n,k),k=1..kk);

Where ap[k] and a[n] are the unknowns.

I want to convert the two equations in the Matrix form A*X=b to solve it numerically and where X=[ap[k, k=1..kk] and a[n, n=1..nn]] and A the matrix with a rand (nn+kk,nn+kk) the coef and b the second member and a vector (nn+kk)

Thank you for any help to do this with Maple

## RootOf(_Z+h*tan(_Z)*b)...

Maple 14

Hi all,

When I solved:

restart: mu:=solve(h*sin(mu*b)+mu*cos(mu*b)=0,mu,AllSolutions=true);

where b and h are constant, the solution is:

...

## solve _C1*sin(lambda*L)...

Maple 14

Hi,

When I solve this equation

Y(lambda):=_C1*sin(lambda*L);

solve(Y(lambda)=0,lambda);

Where _C1 and L are constants, I get 0.

But the solution of this equation which is easy is lambda=n*Pi/L where n=1,2,3,...

Why?

Thanks

## Laplace equation...

Maple 14

Hi all,

I want to get the general solution of the Laplace equation with boundary conditions below:

sys[1] := [diff(A(r, theta), r, r)+(diff(A(r, theta), r))/r+(diff(A(r, theta), theta, theta))/r^2 =0, D[2](A)(r, theta0) = 0, D[2](A)(r, theta0+beta) = 0, D[1](A)(R1, theta) = 0, A(R2,theta)=f(theta)];

pdsolve(sys[1]); do not give me the solution

Thank you to help to obtain the general solution and how (the method) to obtain this solution with Maple

## Laplace equation...

Maple 14

Hi all,

Is there any way with "pdsolve" or 'dsolve' to get the general solution of Laplace equation in polar coordinates with boundary onditions as :

restart:sys[1] := [diff(A(r, theta), r, r)+(diff(A(r, theta), r))/r+(diff(A(r, theta), theta, theta))/r^2 =0, D[2](A)(r, theta0) = 0, D[2](A)(r, theta0+beta) = 0, D[1](A)(R1, theta) = 0, A(R2,theta)=f(theta)];

pdsolve(sys[1]);