SOLUTION: find the exact solutions of 2cos^2x=1 for the interval 0<x<2pi, i missed a few days of school so i have no clue how to do these types of problems because my teacher decided to not

Algebra ->  Trigonometry-basics -> SOLUTION: find the exact solutions of 2cos^2x=1 for the interval 0<x<2pi, i missed a few days of school so i have no clue how to do these types of problems because my teacher decided to not       Log On


   

Question 691917: find the exact solutions of 2cos^2x=1 for the interval 0
Answer by lwsshak3(11628) About Me  (Show Source):
You can put this solution on YOUR website!
find the exact solutions of 2cos^2x=1 for the interval (0,2π)
2cos^2x=1
cos^2x=1/2
take sqrt of both sides
cosx=±1/√2=±√2/2
x=3π/4 and 5π/4 in quadrants II and III where cos<0
and
x=π/4 and 7π/4 in quadrants I and IV where cos>0