The Curve $x = 5 - 10 \cos ^ { 2 } t , y = \tan t \left( 1 - 2 \cos ^ { 2 } t \right)$

Short Answer

The curve $x = 5 - 10 \cos ^ { 2 } t , y = \tan t \left( 1 - 2 \cos ^ { 2 } t \right)$ cross itself at some point $\left( x _ { 0 } , y _ { 0 } \right)$ . Find the equations of both tangent lines at that point.