Generalizing the Product Rule The Derivative Product Rule gives the formula \(\frac { d } { d x } ( u v ) = u \frac { d v } { d x } + \frac { d u } { d x } v\) for the derivative of the product \(u v\) of two differentiable functions of \(x\) .
a. What is the analogous formula for the derivative of the prod- uct \(u v w\) of three differentiable functions of \(x\) ?
b. What is the formula for the derivative of the product \(u _ { 1 } u _ { 2 } u _ { 3 } u _ { 4 }\) of four differentiable functions of \(x\) ?