(sect + tant)^2=(1+sint)/(1-sint)?

Question

I need help please.

Answer 1

LHS
(1 / cos t + sin t / cos t) ²
(1 + sin t ) ² / cos ² t
(1 + sin t) ² / (1 - sin ² t)
(1 + sint ) ² / (1 - sin t) (1 + sin t)
(1 + sin t) / (1 - sin t)

RHS
(1 + sin t) / (1 - sin t)

LHS = RHS