# How to draw double integral functions

by matinking
Tags: double, draw, functions, integral
 P: 17 Hi every one! I would like to draw a double integral function in related to R and h parameters by below M-File but It does goes wrong!!! Is there any one to correct it for me??? thank you syms R h; a1 = 0; a2 = atan(R./(R+h)); r1 = h; r2 = sqrt(R.^2+(R+h).^2); integrand = @(r,a)(h.*sin(a)/((r.^2).*(r.^2+h.^2-2.*r.*h.*cos(a)))); f = quad2d(integrand,r1,r2,a1,a2); ezsurf(f,[0.001,5]);
 PF Patron P: 162 There's two problems that I can see right away (and perhaps more that I don't see). For one I'm guessing you're trying to make f a function of R and h? But you just leave them as symbolic objects. The second problem is that where you define the integrand, you need an extra "." integrand = @(r,a)(h.*sin(a)./((r.^2).*(r.^2+h.^2-2.*r.*h.*cos(a)))); If I understand what you're trying to do correctly then this should do it: f = @(h,R) quad2d(@(r,a)(h.*sin(a)./((r.^2).*(r.^2+h.^2-2.*r.*h.*cos(a)))),h,sqrt(R.^2+(R+h).^2),0,atan(R./(R+h))); ezsurf(f,[0.001,5]); When I ran it, there were a bunch of warnings but I think that may be due to a singularity in the integral you're evaluating.
 P: 17 Thank you very much. your correctness lets the functions be drawn!!!!!

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