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Question
Prove the following identity:
(sin2θ – 1)(tan2θ + 1) + 1 = 0
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Solution
L.H.S. = (sin2θ – 1)(tan2θ + 1) + 1
= (– cos2θ) sec2θ + 1
= `- cos^2θ xx 1/(cos^2θ) + 1`
= –1 + 1
= 0
= R.H.S.
Hence Proved.
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