Defining vector of integrals with undefined function

Hi! What I'd like to do is to define a function r, which takes a function f and a partition xi as arguments. r would be a vector, which elements would be defined by the integral from 0 to 1 of f*bj. Where f is the given function and the bj's are functions defined before in my program. The only thing that really matters for these functions are that they depend on x.

My problem is I don't really know how to do this. Here's my lattest attempt. Thanks for the help!

function int_r=r(f,xi)

n=size(xi,2);

int_r=zeros(1,n);

for j=1:n

int_r(j)=integrate(@(x)f(x)*b(j,x,xi),0,1));

end

end