Question

1) 4+5tg^2x * cos^2x , если sinx = 1/√5

Answer 1

$4 + 5 \times \frac{ { \sin(x) }^{2} }{ { \cos(x) }^{2} } \times { \cos(x) }^{2} = \\ 4 + 5 { \sin(x) }^{2} = \\ 4 + 5( { \frac{1}{ \sqrt{5} } })^{2} = 5$