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Derive cos2x=1-(tan)2x/1+(tan)2x |
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Answer» LHS, We have, cos 2x = cos²x - sin²x = (cos²x - sin²x) / 1 = (cos²x - sin²x) / (cos²x + sin²x) = {cos²x[1-(sin² X/cos² x)]} / {cos²x[1+(sin²x/cos²x)]} ⇒ cos2x = (1 - tan²x) / (1 + tan²x)= RHS Hence Proved !! |
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