$\displaystyle\pi\usepackage{cmbright}\Huge\$ radians corresponds to the point $\displaystyle{\left(-{1},{0}\right)}\usepackage{cmbright}\Huge\$ on the unit circle. The coordinates of this point give you the values of $\displaystyle{\cos{\pi}}\usepackage{cmbright}\Huge\$ and $\displaystyle{\sin{\pi}}\usepackage{cmbright}\Huge\$ . Therefore, you can use the point $\displaystyle{\left(-{1},{0}\right)}\usepackage{cmbright}\Huge\$ to find a point on the graph of sine or cosine, but the point $\displaystyle{\left(-{1},{0}\right)}\usepackage{cmbright}\Huge\$ is not on either of those graphs.