Sinusfunktion

                sin(x) = ±√(0,85) = ±0,921954         x ∈ [0,2π[
 

                      sin(x) = 0,921954

                                        x₁ = 1,1731                      x₂ = (π-x₁) = 1,9685

                      sin(x) = -0,921954

                                        x₃ = (x₁+π) = 4,3147        x₄ = (x₂+π) = 5,1101

da

           sin(x) = sin(π-x)

           sin(-x) = -sin(x) = sin(x+π)