You probably recognized that the graph of sine has one hill with a high point, and one valley with a low point, where the function equals 1 and $\displaystyle-{1}\usepackage{cmbright}\Huge\$ . However, you chose the wrong angles for these two points. The correct answer is: when $\displaystyle\theta=-\frac{{{7}\pi}}{{2}}\usepackage{cmbright}\Huge\$ , $\displaystyle{\sin{\theta}}={1}\usepackage{cmbright}\Huge\$ ; when $\displaystyle\theta=-\frac{{{5}\pi}}{{2}}\usepackage{cmbright}\Huge\$ , $\displaystyle{\sin{\theta}}=-{1}\usepackage{cmbright}\Huge\$