Please help with 38 , 39, 41, 43, 45, 47 and 49

37. 9cos(20) = 9cos2 0 - 4 38. sin(2t) = cos t 39. cos(2t) = sin t 40. cos(6x) - cos(3x) = 0 For the following exercises, solve exactly on the interval [0, 27). Use the quadratic formula if the equations do not factor. 41. tan' x - V 3tan x = 0 42. sin2 x + sin x - 2 = 0 43. sin2 x - 2sin x - 4=0 44. 5cos2 x + 3cos x - 1 =0 45. 3cos2 x - 2cos x - 2 = 0 46. 5sin2 x + 2sin x - 1=0 47. tan' x + 5tan x - 1 = 0 48. cot' x = -cot x 49. -tan x - tan x - 2 = 0