Question #7bd62

1 Answer
Dec 3, 2016

(tan^2x )(csc^2x -1) =(tan^2x)((1+cot^2x)-1) =tan^2xcot^2x=1(tan2x)(csc2x1)=(tan2x)((1+cot2x)1)=tan2xcot2x=1

Explanation:

The basic "Pythagoras" trig relationship is:
sin^2x+cos^2x=1sin2x+cos2x=1, from which you get the other two by dividing both sides either by sin^2xsin2x or cos^2xcos2x:
1+cot^2x=csc^2x1+cot2x=csc2x and tan^2x+1=sec^2xtan2x+1=sec2x.

Remember that by definition cotx=1/tanxcotx=1tanx, secx=1/cosxsecx=1cosx and csc x=1/sinxcscx=1sinx.