@Kitonum I'm very grateful for you

@Kitonum Thanks Kitonum.

Could you tell me waht are you doing when the displacements are functions of x or y

@Mac Dude This problem is a part from a long file. I can not separate this part because it depends on the pervious parts

@rlopez Thanks for your answer. I'll try to do

@Joe Riel Thanks for all.

The integral must be there, that is a closed path for the integral. But,  I want to calculate the integral at each point at the line connected the point [0,2Pi].

@Thomas Richard 

Dears Thomas.  it works well for this simple exampe.   but if we take

sum((-1)^n/n^3*sin(Pi*n/a*x),n=1..infinity)

or   

sum((-1)^n-1/n^3*sin(Pi*n/a*x),n=1..infinity)

the resluts contain polylog funtion  where the summation for these series are well defined.

also, if i take the following series

sum((-1)^n * sinh(Pi*n/a*y)*sin(Pi*n/a*x)/(n^3 * sinh(n*Pib/a)),n=1..infinity), what is the sitiuation.

I do this now,  waiting the program run

I do this now,  waiting the program run

Thank you for your notice but the problem is different here. Before on 13 jan 2013 the problem is technical with program and it solved.

But now the file is so large and contains a lot of system of equations and my Ram is 2 Giga, the program is working and when it reaches to 1370 M or more, it stops.

I want to use the virtual memory for the computer.

@Carl Love 

Ok finally  X=M^-1 * A^T*B       This is a typing mistake

The original problem is still found

thank you pagan  that is what I realy want.

thank you pagan  that is what I realy want.

But if I have a numeric values for the function and numeric values for the variables is there a method to do it like one dimension

plot(<v|F>)   where v and F are vector 

thanks

But if I have a numeric values for the function and numeric values for the variables is there a method to do it like one dimension

plot(<v|F>)   where v and F are vector 

thanks

@Jarekkk 

thanks at all Jarekkk, I am grateful to you