SOLUTION: Find all the solutions in the interval [0, 2𝜋) cos^2(x)+2cos(x)+1=0 Thank you!

Algebra ->  Trigonometry-basics -> SOLUTION: Find all the solutions in the interval [0, 2𝜋) cos^2(x)+2cos(x)+1=0 Thank you!      Log On


   

Question 1131543: Find all the solutions in the interval [0, 2𝜋)
cos^2(x)+2cos(x)+1=0
Thank you!
Answer by MathLover1(20850) About Me  (Show Source):
You can put this solution on YOUR website!

cos%5E2%28x%29%2B2cos%28x%29%2B1=0
%28cos%28x%29%2B1%29%5E2=0
solution:
cos%28x%29%2B1=0=>cos%28x%29=-1
x=pi or x=180°