Question

sec ^4-tan^4=1+2 tan^2

Answer 1

Hope this helps you ☺☺☺

Answer 2

sec^4A-tan^4A=1+2tan²A

LHS:
=sec^4A-tan^4A
=(sec²A)²-(tan²A)²
=(sec²A+tan²A)(sec²A-tan²A)
=[(1+tan²A)+tan²A] (1)
[USING sec²A-tan²A=1]
=(1+tan²A+tan²A)
=(1+2tan²A)
=RHS

Hence proved.