Помогите пожалуйста решить уравнения.Очень срочно нужны.Спасибо!

1. 1 + cosx + cos2x = 0.

2. 6sin^2*x + 5cosx - 7 = 0.

3. cos2x + 3sinx = 0

4. 2cos:2*x + 4cosx = 3sin^2*x.

5. (корень из2)*sinx - cosx = 0.

6. 2sin^2*x + 3cosx = 3.

7. 2sin^2*4x + 3cos4x = 3.

8. sin2x = cosx.

9. cos^2*3x + 5cos3x = 2sin^2*3x.

10. sin6x - sin2x = 0.

11. cos^2*x - 3cosx sinx + 1 = 0.

12. sin4x - cos(p/2 - 3x) = 0.

13. ctgx + 3tgx = 4.

14. 2cos2x - 3sin2x + 2 = 0.

15. cos^2*x - sin^2*x = sin4x.

16. cos2x + 3 = 2sin^2*x.

17. 1 - cos6x = sin3x.

18. 2sin^2*3x + 3cos^2*3x = 2.

19. cos*x + cos*5x + 2cos^2*x = 1.

20. sin^2*4x + sin^2*8x = 1.