(1+cos2a)*-tg(a)=-(2cos^2a)*(sina/cosa)=2cosasina=sin2a
1) sin(3π/2-x)=1/3
3π/2-x=(-1)^k * arcsin(1/3)+πk, k∈Z
-x=(-1)^k * arcsin(1/3)-3π/2+πk, k∈Z
x=(-1)^k+1 * arcsin(1/3)+3π/2-πk, k∈Z
2) cos(2x-π/3)=-1
2x-π/3=π-2πk, k∈Z
2x=π+π/3-2πk, k∈Z
x=2π/3-πk, k∈Z
10!(10-1)! * 9!(9-1)! * 8!/(8-1)! = 10!/9! * 9!/8! * 8!/7! = 10*9*8 = 720 способов