SOLUTION: Hello tutor I am really struggling with this question and require your help please. Solve for x: 3 + cos 2x = 7/2; only include answers on [0, 2π]

Algebra ->  Trigonometry-basics -> SOLUTION: Hello tutor I am really struggling with this question and require your help please. Solve for x: 3 + cos 2x = 7/2; only include answers on [0, 2π]      Log On


   

Question 971858: Hello tutor I am really struggling with this question and require your help please.
Solve for x: 3 + cos 2x = 7/2; only include answers on [0, 2π]
Answer by Boreal(15235) About Me  (Show Source):
You can put this solution on YOUR website!
3 + cos 2x = 7/2
cos 2x=1/2 subtracting 3 or 6/2.
cos 2x= 1-2 sin^2 x =1/2
subtract 1 from both sides
-2 sin^2 x =-1/2
2sin^2 x = 1/2
sin^2 x =1/4
sin = +/- 1/2
This occurs at pi/6, 5 pi/6, 7 pi/6, 11 pi/6