соs2х + sin²х= 0,5
Cos²x - Sin²x +Sin²x = 0,5
Cos²x = 0,5
Cos x = √1/2 или Cos x = -√1/2
x = ±π/4 + 2πk; x = ±(π - π/4) + 2πn;
k€R x = ±3π/4 + 2πn; n€R.
ответ: x = ±π/4 + 2πk, k€R ; x = ±3π/4 + 2πn, n€R.
