# MATLAB: How to integrate an array properly in matlab

arraysintegration

Hello, I am trying to finish a m-file to find the inductance in 2 coils. I have finished the program to the point of integration. I believe the problem is the integration of an array. I have tried various methods such as int, trapz, and quad but all of these seem to be returning an error. I am not sure as to whether I am implementing the commands wrong or rather I have a bad equation. Here is my code
``% This program finds mutual inductance for TET coil system %% Using Neumann's definition %% M = sqrt(ap*as)*(1/(2*pi))*(int(((cos(theta)-(d/as)*((cos(psi)*cos(phi))-(sin(psi)*sin(phi)*cos(theta))))/(R^(3/2)))*f,phi,0,2*pi))%% Increment angles%psi = [0:1:90];%theta = 0:1:90;%phi = 0:1:90;psi = input('Enter psi value in degrees \n')theta = input('Enter theta value in degrees \n')phi = input('Enter phi value in degrees \n')% Arguments%dim = 0:2*pih = input('Enter h value in mm \n')ap = input('Enter ap value in mm \n')as = sqrt((ap^2)-(h^2))delta = h/apalpha = as/apd = h.*tan(phi)Ra = (1-(cos(phi).*cos(phi).*sin(theta).*sin(theta)))Rb = ((2)*(d/as)).*((sin(psi).*sin(phi))-(cos(psi).*cos(phi).*cos(theta)))Rc = ((d.^2)/(as.^2))R = sqrt(Ra+Rb+Rc)z = delta-(alpha*sin(theta)*cos(phi))%kprime_2 = (((1-(alpha.*R)).^2)+z.^2)/(((1+(alpha.*R)).^2+z.^2))kprime_2a = ((1-(alpha.*R)).^2)+z.^2kprime_2b = ((1+(alpha.*R)).^2)+z.^2kprime_2 = kprime_2a./kprime_2bf = -0.011*(log(kprime_2))-0.0021integrand = ((cos(theta)-(d/as).*((cos(psi).*cos(phi))-(sin(psi).*sin(phi).*cos(theta))))/(R.^(3/2))).*f%integrand1 = double(int(((cos(theta)-(d/as).*((cos(psi).*cos(phi))-(sin(psi).*sin(phi).*cos(theta))))./(R.^(3/2))).*f,phi,0,2.*pi))%integrand = double(integrand);stuff = trapz(phi,integrand)M = sqrt(ap.*as).*(1/(2*pi)).*stuff``
I am setting psi and phi to 0 and setting theta to 0:10:90. H is usually 3 and ap is usuall 6. This gives me different error messages for each method of integration I use.
Any help would be appreciated. Thanks.

``function y = inductanceIntegrand(theta,psi,phi,h,ap)as = sqrt((ap^2)-(h^2));delta = h/ap;alpha = as/ap;d = h.*tan(phi);Ra = (1-(cos(phi).*cos(phi).*sin(theta).*sin(theta)));Rb = ((2)*(d/as)).*((sin(psi).*sin(phi))-(cos(psi).*cos(phi).*cos(theta)));Rc = ((d.^2)/(as.^2));R = sqrt(Ra+Rb+Rc);z = delta-(alpha*sin(theta).*cos(phi));kprime_2a = ((1-(alpha.*R)).^2)+z.^2;kprime_2b = ((1+(alpha.*R)).^2)+z.^2;kprime_2 = kprime_2a./kprime_2b;f = -0.011*(log(kprime_2))-0.0021;y = sqrt(ap.*as).*(1/(2*pi)).*((cos(theta)-(d/as).*((cos(psi).*cos(phi))-(sin(psi).*sin(phi).*cos(theta))))/(R.^(3/2))).*f;``
``psi = 0;phi = 0;h = 3;ap = 6;f = @(theta) inductanceIntegrand(theta,psi,phi,h,ap);M = quadl(f,0,2*pi);disp(M)-4.5074e-04``