SOLUTION: Find x if 0 < x< 2x and 1+ cosx = 4sin^2x.

Algebra ->  Trigonometry-basics -> SOLUTION: Find x if 0 < x< 2x and 1+ cosx = 4sin^2x.      Log On


   

Question 934381: Find x if 0 < x< 2x and 1+ cosx = 4sin^2x.
Answer by lwsshak3(11628) About Me  (Show Source):
You can put this solution on YOUR website!
Find x if 0 < x< 2π and 1+ cosx = 4sin^2x
***
1+cosx=4sin^2x
1+cosx=4(1-cos^2x)
1+cosx=4-4cos^2x
4cos^2x+cosx-3=0
(4cosx-3)(cosx+1)=0
..
4cosx-3=0
cosx=3/4
x≈0.72,5.56
or
cosx+1=0
cosx=-1
x=π