2.3 The Product Rule If h(x) = f(x)g(x), then h'(x)= f'(x)g(x)+ f(x)g'(x) Proof from first principles (i.e., limit definition) Similarly, if y = f(x)g(x)h(x), then y= f'(x)g(x)h(x)+ f(x)g'(x)h(x)+ f(x)g(x)h'(x) Ex.2 Find the point(s) on the curve which satisfy: f(x)=2(x-1)(5-x) and mangent=4 Ex.1 Find the derivative of each function (using the product rule). (a) y=(2x+4)(3x-5) (b) f(x)=(3x+4x-6)(2x -3x-9) Ex 3 Determine the point(s) where the tangent to y=3(x-4)(x-4)(x-1) is horizontal. 10