Question

Prove: tan2 θ•cos2 θ + cos2 θ = 1.
I can not figure out how to answer this question!
please help!

Answer 1

\[\tan^2 \Theta = \frac{ \sin^2 \Theta }{ \cos^2 \Theta }\]
\[\tan^2 \Theta * \cos^2 \Theta = \sin^2 \Theta\]
\[\sin^2 \Theta + \cos^2 \Theta = 1\]
1 = 1