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Prove that (cos 7x + cos 5x /sin 7x - sin5x) = cot x |
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Answer» cos7x+cos5x = 2cos6xcosx sin7x-sin5x = 2cos6xsinx (cos7x+cos5x)/(sin7x-sin5x) = 2cos6xcosx/2cos6xsinx = cotx |
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