The graph of sine has a hill from $\displaystyle\theta=-{4}\pi\usepackage{cmbright}\Huge\$ to $\displaystyle\theta=-{3}\pi\usepackage{cmbright}\Huge\$ . In the middle of the hill the function has a high point, where it is equal to 1. This point occurs where $\displaystyle\theta=-{3.5}\pi=-\frac{{{7}\pi}}{{2}}\usepackage{cmbright}\Huge\$ . The graph has a valley from $\displaystyle\theta=-{3}\pi\usepackage{cmbright}\Huge\$ to $\displaystyle\theta=-{2}\pi\usepackage{cmbright}\Huge\$ . In the middle of the valley the function has a low point, where it is equal to $\displaystyle-{1}\usepackage{cmbright}\Huge\$ . This point occurs where $\displaystyle\theta=-{2.5}\pi=-\frac{{{5}\pi}}{{2}}\usepackage{cmbright}\Huge\$ .