Question

Decide whether the equation is a trigonometric identity. Explain your reasoning.

1. cos^2 x (1+tan^2 x) =1

Answer 1

i got yes

Answer 2

sec^2 x = 1 + tan^2 x
so substituting:
= cos^2 x * sec^2 x
but sec^2 x = 1/cos^ 2

so - can you see the way to go?