Use a function handle inside another function handle

I need to find out the integral of some function Let's say f(x).*sin(x). I define a function handle y=@(x)f(x); Now I want to define another function handle z as z = @(x)y.*sin(x) so that I can integrate: int = integral(z,x1,x2). Matlab does not allow me to do this. Is there a way so I can define the function separately and then define the function handle for the integrand?

Answer 1

[Steven Lord]

You're missing one small piece in your definition of z. You can't multiply a function handle and a numeric value, but you can multiply the numeric value obtained by evaluating that function handle and a numeric value.

 f = @cos;
 y = @(x) f(x);
 z = @(x) y(x).*sin(x); % Note y(x) instead of y

To test, compare evaluating the function using the function handle and evaluating the function normally, by calling COS and SIN:

 v = 0:0.1:2*pi;
 usingFH = z(v);
 usingFun = cos(v).*sin(v);
 isequal(usingFH, usingFun)

That last statement will return true.

[Sudipta Ray]

Thank you Steven. It worked perfectly. I should have known, Matlab was giving me this error "operator '*' undefined for function handle". Now it is working fine. I needed this because I want to use different functions as an input.