Show That $$\left( - \frac { 1 } { 8 } , \frac { 3 , \sqrt { 7 } } { 8 } \right)$$

Essay

Show that $$\left( - \frac { 1 } { 8 } , \frac { 3 , \sqrt { 7 } } { 8 } \right)$$ is on the unit circle.