Question

I am trying to figure this question:

1 + tan^2A = Sec^2A

Answer 1

see explanation

Explanation:

Using the Pythagorean identity

cos²A + sin²A = 1 ( divide terms by cos²A )

`(cos^2A)/(cos^2A)` +
`(sin^2A)/(cos^2A)` =
`(1)/(cos^2A)` , that is

1 + tan²A = sec²A ← as required