Question

1) cos(2arctg(-1))
2) arcsin(sin$frac{3 pi }{3}$)
3) sin(arccos(-$frac{1}{2}$)

Answer 1

1) =cos(2*3π/4)=cos(3π/2)=0
2) =arcsin(sinπ)=π
3) =sin(2π/3)=(√3)/2