Question

2sin^2 x-6cos x + 6 =0​

Answer 1

2Sin²x - 6Cosx + 6 = 0

2(1 - Cos²x) - 6Cosx + 6 = 0

2 - 2Cos²x - 6Cosx + 6 = 0

2Cos²x + 6Cosx - 8 = 0

Cos²x + 3Cosx - 4 = 0

Cosx₁ = - 4 - неуд , так как - 1 ≤ Cosx ≤ 1

Cosx₂ = 1

x = 2πn , n ∈ Z