Integration help (quad)

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{:});

[John D'Errico]

So what error did you get???? You only wrote part of the error here, the part that gives insufficient information!

Answer 1

[Matt Fig]

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)

Answer 2

[Friedrich]

Hi Jeffrey,

I think you get this error because of the extra dot after sin(theta). You function rfun should look like this:

function y=rfun(theta)

      y=(cos(theta).*sin(theta));
end

I hope I could help, Friedrich

Answer 3

[Jeffrey]

Thanks Friedrich and Matt.

Jeff