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Prove tan (45+a) = cos2a / 1-sin2a |
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Answer» Answer:Proved Step-by-step explanation:tan(π/4+a) tan(a+b)=tan a+tan b/(1-tan a tan b) tan(π/4+a)=tan π/4+tan a/1-tan π/4 tan a tan(π/4+a)=1+tan a/1-tan a tan(π/4+a)=(1+sin a/cosA)/(1-sin a/COS a) tan(π/4+a)=(cos a+sin a)/(cos a-sin a) RATIONALISING, we GET (cos a+sin a)(cos a-sin a)/(cos a-sin a)(cos a-sin a) cos²a-sin²a/(cos a-sin a)² cos 2a/(cos²a+2sin a cos a+ sin²a) Since cos²a+sin²a=1 cos 2a/1-sin 2a Proved |
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