When you draw an angle in standard position and it intersects the unit circle at the point $\displaystyle{\left({x},{y}\right)}\usepackage{cmbright}\Huge\$ , the x-coordinate gives you the value of the cosine function at that angle, and the y-coordinate gives you the value of the sine function at that angle. This information will be used to help you find points on the graph of the sine and cosine functions, but the point $\displaystyle{\left(-{1},{0}\right)}\usepackage{cmbright}\Huge\$ itself is not on the graph of $\displaystyle{y}={\cos{\theta}}\usepackage{cmbright}\Huge\$ .