Q38 of 51 Page 54

If tan2 a – tan2 b. Prove that: .

Formula: -


(i) tan2x = sec2x – 1


(ii) cos2x = 1 – sin2x


Taking L.H.S and applying formula (i) we get,


tan2A – tan2B = sec2A – 1 – (sec2B – 1)


⇒ tan2A – tan2B = sec2A – 1 – sec2B + 1


⇒ tan2A – tan2B = sec2A – sec2B





Applying formula (ii) we get,




L.H.S = R.H.S


Hence, Proved.


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