1.sin-(x)=sin 2пи 2.sin(пи/2-x)=sin пи/4

1. sin(-x) = sin(2π)
sin(-x) = 0
-x = πn, n ∈ Z
x=-πn, n ∈ Z

2. sin(π/2-x)=sin(π/4)
sin(π/2-x) = sqrt(2)/2
π/2-x = π/4 + 2πn, n∈Z и 3π/4 + 2πn
-x = -π/4 + 2πn и π/4 + 2πn, n∈Z
x = +- π/4 + 2πn, n∈Z