Question

Сократите cosa+sina*ctga

Answer 1

cos a+sin a * cos a/sin a=cos a + cos a=2cos a

Answer 2

Ответ: $2cos(\alpha )$

$cos (\alpha) + sin(\alpha )*ctg(\alpha) = cos(\alpha ) + sin(\alpha ) * \frac{cos(\alpha )}{sin(\alpha )} = cos(\alpha ) + cos(\alpha ) = 2cos(\alpha )$