Question

How do you perform addition or subtraction and use the fundamental identities to simplify `1/(secx+1)-1/(secx-1)`?

Answer 1

`1/(secx+1)-1/(secx-1)=-2cot^2x`

Explanation:

`1/(secx+1)-1/(secx-1)`

= `(secx-1-secx-1)/(sec^2x-1)`

= `-2/tan^2x`

= `-2cot^2x`