Hey there
Your question is incomplete please mention about X you missed X from the question. This is a simple trigonometry question though you can solve it by using conversion formula for hyperbolic functions this way you'll not have to mess with the question.
Good luck
Question : If $\cos^2x+\cos^4x=1$, then $\tan^2x+\tan^4x$?
Option 1: $0$
Option 2: $1$
Option 3: $2 \tan^2x$
Option 4: $2\tan^4x$
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