Correct. The values of this function range from $\displaystyle-{2}\usepackage{cmbright}\Huge\$ to 2, so the amplitude is 2. This means $\displaystyle{a}=\pm{2}\usepackage{cmbright}\Huge\$ . Because the sine graph has not been reflected over the x-axis, a must be positive. So $\displaystyle{a}={2}\usepackage{cmbright}\Huge\$ . Four cycles are shown over the interval $\displaystyle{\left[{0},{2}\pi\right]}\usepackage{cmbright}\Huge\$ . This implies that $\displaystyle{b}={4}\usepackage{cmbright}\Huge\$ .