Question

cos a- sin a/sin a* cos a +sin a/ 2cos a

Answer 1

(sin(3П/2+a)+sin(2П+a)/(2cos(-a)sin(-a)+1)=

=-cos a + sin a / (2 cos a * (-sin a) +1) =

=-cos a + sin a / (-2 cos a * sin a + (cos a)^2 +2 cos a * sin a + (sin a)^2 )=

= -cos a + sin a /  ((cos a)^2  + (sin a)^2) =

= -cos a + sin a / 1 = sin a - cos a

Источник: http://znanija.com/task/210214