Chapter 3 - Differentiation - 3.2 The Derivative as a Function - Preliminary Questions - Page 114: 3

a) $ f(x) = x^2 $ c) $ f(x) = x ^\pi$ f) $ f(x) = x^\frac{-4}{5} $

The power rule applies only when a variable is raised to a constant power. We rule b) $ f(x) = 2\pi$ and d) $f(x) = \pi^x$ out because the value being raised is a constant. We rule e) $f(x) = x^x $ out because the variable is not being raised to a constant power.