A) sin(x) = 1/2
x = (-1)^k * arcsin(x) + pn, n E Z.
x = p/6 + pn, n = 0...2
x = -p/6 + pn, n = 1...3
b) sin(x) = -1/2
x = (-1)^k * arcsin(x) + pn, n E Z.
x = -p/6 + pn, n = 0...2
x = p/6 + pn, n = 0...1
в) и г) аналогично, сам справишься? arcsin(sqrt(2)/2) = p/4.