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12 Find 1-cos 20 |
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Answer» cos(2x) = cos^2x - sin^2x sin(2x) = 2sinxcosx tanx = sinx/cosx Proving: = (1 - cos(2x)) / sin(2x) = (1 - (cos^2x - sin^2x)) / 2sinxcosx = (1 - cos^2x + sin^2x) / 2sinxcosx = (sin^2x + sin^2x) / 2sinxcosx = 2sin^2x / 2sinxcosx = sinx/cosx = tanx Like my answer if you find it useful! |
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