Chapter 10 - Section 10.5 - Derivatives: Numerical and Graphical Viewpoints - Exercises - Page 754: 71

Increasing: $x\lt0$ Decreasing: $0\lt x$

Increasing means that the derivative of a function, $f'$, is greater than $0$ ($f'\gt0$). That is, the graph of $f'$ is above the x-axis. This happens when $x\lt0$ Decreasing means that the derivative of a function, $f'$, is less than $0$ ($f'\lt0$). That is, the graph of $f'$ is below the x-axis. This happens when $0\lt x$