There are special cases in which the derivative of (x)g(x) does equal (x)g(x). Calculate both [(x)g(x)] and

There are special cases in which the derivative of ƒ(x)g(x) does equal ƒ′(x)g′(x). Calculate both [ƒ(x)g(x)] and ƒ′(x)g′(x) for ƒ(x) = a/(1 - x) and g(x) = bx, and verify that the two expressions are equal.