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 $\tan^2x+\tan^4x$?
Regular exam updates, QnA, Predictors, College Applications & E-books now on your Mobile