Question

Simplify (1 − sin x)(1 + sin x)

1

cos2 x

sin2 x

tan2 x

Answer 1

I think it's B

Answer 2

distribute: 1 - sin2x
using the identity 1 = sin2x + cos2x
it's equal to cos2x so yes you're correct

Answer 3

Oh, ok. Thanks, I didn't do it that way. Is that the proper way to do it?

Answer 4

In trigonometry you can solve equations in many ways

There's really no "proper" way to do it. Unless you were guessing