Question

(1+cos a)ctg2a(1-cos a) ??

Answer 1

1. ctg(2)=(cos(2)/sin(2))

2. (1+cos(a))*cos(2)=cos(2)+cos(a)*cos(2)

3. (cos(2)+cos(a)*cos(2))/sin(2)=cos(2)/sin(2)+cos(a)*cos(2)/sin(2)

4. (cos(2)/sin(2)*a+cos(a)*cos(2)/sin(2)*a)*(1-cos(a))
5. cos(2)/sin(2)*a-(cos(a))^2*cos(2)/sin(2)*a