SOLUTION: 2cos(theta)+1=0 i need help finding all soultions from 0< theta<360

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Question 1155498: 2cos(theta)+1=0
i need help finding all soultions from 0< theta<360
Answer by MathLover1(20850) About Me  (Show Source):
You can put this solution on YOUR website!

2cos%28theta%29%2B1=0
2cos%28theta%29=-1
cos%28theta%29=-1%2F2
theta=cos%5E-1%28-1%2F2%29
theta=%282Pi%29%2F3

given: 0%3C+theta%3C360
=>theta=%282Pi%29%2F3, theta=%284Pi%29%2F3
=>theta=120°, theta=240°