The effect of adding $\displaystyle\frac{\pi}{{2}}\usepackage{cmbright}\Huge\$ to the input of the function is to shift the graph of $\displaystyle{y}={\sin{\theta}}\usepackage{cmbright}\Huge\$ to the left by $\displaystyle\frac{\pi}{{2}}\usepackage{cmbright}\Huge\$ units. So, for example, the hill that was on the interval $\displaystyle{\left[{0},\pi\right]}\usepackage{cmbright}\Huge\$ in the graph of $\displaystyle{y}={\sin{\theta}}\usepackage{cmbright}\Huge\$ becomes a hill with the y-axis running through the center in the graph of $\displaystyle{y}={\sin{{\left(\theta+\frac{\pi}{{2}}\right)}}}\usepackage{cmbright}\Huge\$ . The graph of $\displaystyle{y}={\sin{{\left(\theta+\frac{\pi}{{2}}\right)}}}\usepackage{cmbright}\Huge\$ will be the same as the graph of cosine, which is the graph shown.