Решите тригонометрические
уравнения:
1. 10cos^2x + 11cos x – 8 = 0
2. 4cos^2x – 11sin x – 11 = 0
3. 3sin^2x + 8sin x cos x + 4cos^2x = 0
4. 5 tg x – 12ctg x + 11 = 0
5. 5sin 2x + 22sin^2x = 16
6. 2sin^2x – 10cos2x = 9sin 2x + 10