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[tex]sin^{2}1 + sin^{2}2 +sin^{2} 3+.............. +sin^{2}89 = ? |
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Answer» Answer: ANSWER 1+sin2A−cos2A 1+sin2A+cos2A
= sin2A+1−(1−2sin 2 A) sin2A+1+2cos 2 A−1
= 2sinAcosA+2sin 2 A 2sinAcosA+2cos 2 A
= 2SINA(cosA+sinA) 2cosA(sinA+cosA)
= sinA cosA
=COTA. |
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