SOLUTION: solve the equation on the interval [0,2pi] 4cos^2x= 1

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Question 1052111: solve the equation on the interval [0,2pi]
4cos^2x= 1
Answer by ikleyn(52910) About Me  (Show Source):
You can put this solution on YOUR website!
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solve the equation on the interval [0,2pi]
4cos^2x= 1
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4cos%5E2%28x%29 = 1  --->  cos%5E2%28x%29 = 1%2F4  --->  cos(x) = +/-sqrt%281%2F4%29 = +/-1%2F2.


If  cos(x) = 1%2F2  then  x = pi%2F3  OR  x = 5pi%2F3.


If  cos(x) = -1%2F2 then  x = 2pi%2F3  OR  x = 4pi%2F3.


Answer.  The set of solutions is  pi%2F3,  2pi%2F3,  4pi%2F3  and  5pi%2F3.