When $\displaystyle\theta=-{2}\pi\usepackage{cmbright}\Huge\$ , $\displaystyle{\sin{\theta}}={1}\usepackage{cmbright}\Huge\$ ; when $\displaystyle\theta=-{3}\pi\usepackage{cmbright}\Huge\$ , $\displaystyle{\sin{\theta}}=-{1}\usepackage{cmbright}\Huge\$