Question

Question #7d3bd

Answer 1

see below

Explanation:

`cos^2x+cos^4x=1`

`cos^4x=1-cos^2x=sin^2x`

Therefore

`tan^2x+tan^4x=tan^2x(1+tan^2x)`

`=tan^2xsec^2x`

`=sin^2x/cos^2x*1/cos^2x`

`=sin^2x/cos^4x`

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

`=sin^2x/sin^2x`

`=1`