Left Hand Side:
(tan^2x-1)/(cot^2x-1) = (sin^2x/cos^2x -1)/(cos^2x/sin^2x -1)tan2x−1cot2x−1=sin2xcos2x−1cos2xsin2x−1
=(sin^2x/cos^2x -cos^2x/cos^2x)/(cos^2x/sin^2x -sin^2x/sin^2x)=sin2xcos2x−cos2xcos2xcos2xsin2x−sin2xsin2x
=((sin^2x-cos^2x)/cos^2x)/((cos^2x -sin^2x)/sin^2x)=sin2x−cos2xcos2xcos2x−sin2xsin2x
=(sin^2x-cos^2x)/cos^2x *sin^2x/(cos^2x -sin^2x)=sin2x−cos2xcos2x⋅sin2xcos2x−sin2x
=(sin^2x-cos^2x)/cos^2x *sin^2x/(-(sin^2x-cos^2x)=sin2x−cos2xcos2x⋅sin2x−(sin2x−cos2x)
=cancel(sin^2x-cos^2x)/cos^2x *sin^2x/(-cancel(sin^2x-cos^2x)
=sin^2x/(-cos^2x)
=(1-cos^2x)/(-cos^2x)
=1/(-cos^2x) -cos^2x/(-cos^2x)
=1/(-cos^2x)+cancel(cos^2x)/cancel(cos^2x)
=-1/cos^2x +1
=1-1/cos^2x