If you can work this out please try and reply to it before friday the 10th!!! #1: If f is a differentiable function and g(x) = xf(x), use the definition of a derivative to show that g'(x)(g prime of x) = xf'(x)+f(x)(xf prime of x plus f of x). Definition of a Derivative: The Derivative of a function f at a number a, denoted by f'(a) (f prime of a), is: Lim f(a + h) - f(a) x -> 0 -------------- h