Double integration with trapz

Hi everyone! I'm new in matlab,and I'd like using from trapz for solve this equation: exp(r1.*r2)over on the r1 and r2; but I couldn't, for solve this double integration, I expanded exp(r1.*r2) and got the solution but because of I am trying to simulation a laser cavity, that solution is not more exact. so I am hope solve this double integral and I need help. please help me. N=256; a=10e-6; r1=-N/2*a:a:(N/2-1)*a; r2=r1; [R1 R2]=meshgrid(r1,r2)

Answer 1

[Jeremy Kemmerer]

It sounds like you are trying to perform numerical double integration. Have you tried using the function “integral2”?

Here’s how you might do that for your example:

>>fun = @(x,y) exp(x.*y); //handle to function to be integrated

>>llim = -N/2*a; //define limits of integration

>>ulim = (N/2-1)*a;

>>q = integral2(fun,llim,ulim,llim,ulim);

Please refer to the following documentation for more information about the “integral2” function: http://www.mathworks.com/help/matlab/ref/integral2.html

[Habib]

thank you for your reply. I want use from trapz command because its solutions are more exact than the solutions of integral2 command. so how can I do it with trapz command?