Question

\(cos^2\alpha+tg^2\alpha.cos^2\alpha\)

Answer 1

cos 2 α + t g 2 α . cos 2 α = cos 2 α + sin 2 α / cos 2 α . cos 2 α = cos 2 α + sin 2 α = 1

Answer 2

\(cos^2\alpha+tg^2\alpha.cos^2\alpha\)
\(=cos^2\alpha\left(1+tg^2\alpha\right)\)
\(=cos^2\alpha.\dfrac{1}{cos^2\alpha}\)
\(=1\)