Question

How do you prove? #`Sec^4A-sec^2A = tan^4A+tan^2`#

Answer 1

Please see below.

Explanation:

`sec^4A-sec^2A`

= `sec^2A(sec^2A-1)`

= `sec^2Atan^2A`

= `(tan^2A+1)tan^2A`

= `tan^4A+tan^2A`