Prove the following identities.
sec2x−cosec2x≡tan2x−cot2x\sec^2 x - \operatorname{cosec}^2 x \equiv \tan^2 x - \cot^2 xsec2x−cosec2x≡tan2x−cot2x
(secx−cosx)2≡tan2x−sin2x(\sec x - \cos x)^2 \equiv \tan^2 x - \sin^2 x(secx−cosx)2≡tan2x−sin2x