MATLAB: Integration help (quad)

integrationquad

New to Matlab and stuck trying to integrate trigXtrig function.

Here's what I've been doing:

function y=rfun(theta)
y=(cos(theta).*sin(theta).);
end
EDU>> q=quad('rfun',0,0.644)

But I get this error:

Error in ==> quad at 77
y = f(x, varargin{:});

Best Answer

Why not use an anonymous function instead?

>> y = @(th) cos(th).*sin(th); % The function to integrate... 
>> q = quad(y,0,0.644)  % Also, quadl(y,0,0.644)

Related Solutions

MATLAB: Double integral of a dot product error

integral2() assumes that the function handle is able to accept matrix inputs. However, the fun() function in your code does not work correctly with matrix inputs. The following codes shows a quick fix using arrayfun

light_dir = [-0.6626;0;-0.7490];
camera_dir = [-1;0;0];
R = sqrt(2/(4*pi));
x_c =@(theta,phi) R.*sin(theta).*cos(phi);
y_c =@(theta,phi) R.*sin(theta).*sin(phi);
z_c =@(theta) R.*cos(theta);
normal =@(theta,phi) [x_c(theta,phi); y_c(theta,phi); z_c(theta)];
fun = @(theta,phi) (dot(light_dir,normal(theta,phi))).*(dot(camera_dir,normal(theta,phi))<0).*R^2.*sin(theta);
intensity = integral2(@(THETA, PHI) arrayfun(@(theta,phi) fun(theta, phi), THETA, PHI) ,0,pi,0,2*pi);

MATLAB: How to define a function that evaluates in input

function y=T(theta_Degree)
theta=theta_Degree*pi/180;
y=[cos(theta)^2 sin(theta)^2 2*cos(theta)*sin(theta);sin(theta)^2 cos(theta)^2 -2*cos(theta)*sin(theta);-cos(theta)*sin(theta) cos(theta)*sin(theta) cos(theta)^2-sin(theta)^2];
end

Then type in command line

T(40)

and see the results.

Best Answer

Related Solutions

MATLAB: Double integral of a dot product error

MATLAB: How to define a function that evaluates in input

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