ttpp1124 Messages 110 Reaction score 4 Thread starter May 11, 2020 #1 Homework Statement I believed I've proved it right, but can someone confirm? Relevant Equations n/a
member 587159 May 11, 2020 #2 I believe it is correct, but note that $$(\tan^2 x -1)/\sec^2 x = (\tan^2 x -1) \cos^2 x = \sin^2 x - \cos^2 x = - \cos(2x)$$ so you could have been a little faster.
I believe it is correct, but note that $$(\tan^2 x -1)/\sec^2 x = (\tan^2 x -1) \cos^2 x = \sin^2 x - \cos^2 x = - \cos(2x)$$ so you could have been a little faster.