x^3-27y^3-3y-x=x*(x^2-1)-3y*(9y^2+1)
............................
Sin²α = 1 - Cos²α = 1 - (- 3/4)² = 1 - 9/16 = 7/16
32Sin2αSinα = 32 * 2SinαCosα * Sinα = 64Sin²αCosα = 64 * 7/16 * (- 3/4) =
= - 21
6(1 - Cos²x) - Cosx - 5 = 0
6 - 6Cos²x - Cosx -5 = 0
6Cos²x + Cosx -1 = 0
D = 25
Cosx = (-1+5)/12= 1/3 б) Cosx = (-1 -5)/12 = -1/2
x = +-arcCos1/3 + 2πk, k ∈Z x = +-2π/3+ 2πn, n ∈Z