calculate a double integral in a function

I want to calculate this double integral in a function that the inputs are m,n and a two variable function like f(x,y) but I don't know how to pass f(x,y) to function.here is my code

clear;clc;close all;
f = @(x,y) sin(2*x)*sin(y);
Bmn = findBmn(1,2,f);
%%
function Bmn = findBmn(m,n,f)
    a = pi;
    fun = @(x,y) f.*sin(n*pi*x/a).*sin(m*pi*y/a);
    Bmn = (4/(a^2)).*integral2(fun,0,a,0,a);
end

Answer 1

[David Hill]

f = @(x,y) sin(2*x).*sin(y);
Bmn = findBmn(1,2,f)

Bmn = 1.0000

function Bmn = findBmn(m,n,f)
    a = pi;
    fun = @(x,y) f(x,y).*sin(n*pi*x/a).*sin(m*pi*y/a);
    Bmn = (4/(a^2)).*integral2(fun,0,a,0,a);
end