Question

4sina/2*sinП-a/2*sin(3П/2-a)​

Answer 1

Ответ:

sin(п-а/2)=sin(а/2); sin(3/2п-a)=-cos(a)

4*sin(a/2)*sin(a/2)*(-cos(a))

4*sin^2(a/2)*(-cos(a))

2sin^2(a)=1-cos(2a)

2*1-cos(a)*(-cos(a))=-2cos(a)-cos^2(a)