Question

Question #d5338

Answer 1

`LHS=(Sec^2x - 1)/ sin x`

`=tan^2x/ sin x`

`=(sin^2x/cos^2x)/ sin x`

`=(sin^2x/cos^2x)xx1/ sin x`

`=(sinx/cos^2x)`

`= sin x / (1- sin^2 x)=RHS`

So it is an identity

Then

`(Sec^2x - 1)/ sin x = cos x / (1- sin^2x)`

is not an identity