SOLUTION: In the interval 90degrees <= x <= 180degrees find the value of x that satisfies the equation 2cos^2x = 1 I started by dividing both sides by 2cos^2 which left me with X =

Algebra ->  Trigonometry-basics -> SOLUTION: In the interval 90degrees <= x <= 180degrees find the value of x that satisfies the equation 2cos^2x = 1 I started by dividing both sides by 2cos^2 which left me with X =      Log On


   

Question 278800: In the interval 90degrees <= x <= 180degrees find the value of x that satisfies the equation 2cos^2x = 1
I started by dividing both sides by 2cos^2 which left me with
X = 1/2cos^2 now I'm stuck
Answer by Alan3354(69443) About Me  (Show Source):
You can put this solution on YOUR website!
2cos^2x = 1
2%28cos+%28x%29%29%5E2+=+1
%28cos%28x%29%29%5E2+=+1%2F2
cos(x) = +/- sqrt(2)/2
x = 135 degrees