Question

Номер 205,совсем не понимаю эту тему

Answer 1

$(\frac{cos \beta }{sin \alpha }+\frac{sin \beta }{cos \alpha} )*\frac{1-cos4 \alpha }{cos( \pi - \beta + \alpha )}=\frac{cos \alpha cos \beta +sin \alpha sin \beta }{sin \alpha *cos \alpha}*\frac{1-cos^22 \alpha +sin^22 \alpha }{-cos( \alpha - \beta )}= \\ \\ =\frac{cos( \alpha-\beta) }{sin \alpha *cos \alpha}*\frac{sin^22 \alpha +sin^22 \alpha }{-cos( \alpha - \beta )}=-\frac{2sin^22 \alpha }{sin \alpha *cos \alpha }=-\frac{4sin^22 \alpha }{2sin \alpha *cos \alpha }=$
$=-\frac{4sin^22 \alpha }{sin2 \alpha}=-4sin2 \alpha$

Answer 2

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