Question

sec^4x-1/tan^2x

Answer 1

i got to sec^4x-1/sec^2x-1

Answer 2

simplify more the numerator by using (a^2 - b^2 ) = (a+b) (a-b)

Answer 3

Excellent!
\[\frac{sec^4 x -1}{tan^2 x} = \frac{sec^4 x - 1}{sec^2 x - 1} = \frac{(sec^2 x - 1)(sec^2 + 1)}{(sec^2 x - 1)} = sec^2 x + 1\]