Question

-sina ctga cosa=
помогите пожалуйста

Answer 1

$- sin alpha times ctg alpha times cos alpha = - sin alpha times frac{cos alpha }{sin alpha } times cos alpha = - {cos}^{2} alpha$

Answer 2

$- sina times ctga times cosa = - sina times frac{cosa}{sina} times cosa = \ = - cosa times cosa = - {(cosa)}^{2}$



ОТВЕТ: - cos²a