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Question
Prove the following identity :
secA(1 + sinA)(secA - tanA) = 1
Solution
LHS = secA(1 + sinA)(secA - tanA)
= `1/cosA(1 + sinA)(1/cosA - sinA/cosA)`
= `((1 + sinA))/cosA((1-sinA)/cosA) = (1-sin^2A)/cos^2A`
= `(cos^2A/cos^2A) = 1` = RHS
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