Решите тригонометрические уравнения: 1. 3sin^2x – 10sin x + 7 = 0 2. 8sin^2x + 10cos x – 1 = 0 3. 4sin^2x + 13sin x cos x + 10cos^2x = 0 4. 3 tg x – 3ctg x + 8 = 0 5. sin 2x + 4cos^2x = 1 6. 10cos^2x – 9sin 2x = 4cos 2x – 4