The graph starts at $\displaystyle{\left({0},{1}\right)}\usepackage{cmbright}\Huge\$ and decreases to $\displaystyle{\left(\frac{\pi}{{2}},{0}\right)}\usepackage{cmbright}\Huge\$ . Then it decreases to $\displaystyle{\left(\pi,-{1}\right)}\usepackage{cmbright}\Huge\$ and increases to $\displaystyle{\left(\frac{{{3}\pi}}{{2}},{0}\right)}\usepackage{cmbright}\Huge\$ . Finally, it increases to $\displaystyle{\left({2}\pi,{0}\right)}\usepackage{cmbright}\Huge\$ .