Question

1-sin2 альфа+ctg2 альфа×sin2 альфа=

Answer 1

$1-sin2 alpha +ctg2 alpha *sin 2alpha =1-sin2 alpha + frac{cos 2alpha }{sin 2alpha } *sin 2alpha=$

$1-sin2 alpha +cos2 alpha =2cos^ 2alpha -2sin alpha cos alpha =2cos alpha (cos alpha -sin alpha )$