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ii π < 28.5. then y2+V2+2cos 40equal:3) 22)-2 sintů1)-2 cosThe value of cos10° cos30, cos50 oos70 is2)3) |
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Answer» cos10.cos30.cos50.cos70 = 3/16 = cos30.cos10.cos50.cos70 = root(3)/2 × cos10.cos50.cos70 = root(3)/4 × (cos60 + cos40)cos70 = root(3)/8 × 2cos60.cos70 + 2cos40.cos70 = root(3)/8 × (cos70 + cos110 + cos30) = root(3)/8 × (cos70 - cos70 + root(3)/2) = [root(3) × root(3)] / (8×2) = 3/16 like my answer if you find it useful! |
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