Question

упростите

((sinA/1+cosA) +(sinA/1-cosA))×sin2a

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Answer 1

$left(dfrac{sin alpha}{1+cos alpha}+dfrac{sin alpha}{1-cos alpha}right)sin 2alpha=dfrac{sin alpha-cos alpha sinalpha +sin alpha+sin alphacosalpha}{1-cos^2alpha}cdot \ \ \ cdot sin 2alpha=dfrac{2sin alpha}{sin^2alpha}cdot 2sinalphacosalpha=4cos alpha$