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Question
Prove the following identities:
`1 - sin^2A/(1 + cosA) = cosA`
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Solution
`1-sin^2A/(1 + cosA)`
= `(1 + cosA - sin^2A)/(1 + cosA)`
= `(cosA + cos^2A)/(1 + cosA)`
= `(cosA(1 + cosA))/(1 + cosA)`
= cos A
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