How to convert formula like "rho(1), rho(2)...rho(k)" into matlab?

I want to put the following formula into my program:

r(k) = integral[I('x)Pl('x)P2('x)··· Pk('x)d('x)] k>= 1

I know the integral command but in the inner part [[Pl('x)P2('x)··· Pk('x)] i don't know how to do.

Please help