SOLUTION: Find all EXACT solutions of the equation cos(x ) = −1/2 in the interval [0,2π). If there is more than one answer, enter them in a list separated by commas.

Question 1060248: Find all EXACT solutions of the equation
cos(x ) = −1/2
in the interval [0,2π). If there is more than one answer, enter them in a list separated by commas.
Answer by Edwin McCravy(20060) (Show Source): You can put this solution on YOUR website!

The reference angle is the acute angle whose cosine is 1/2.

We can find it on the unit circle:

 .

It is 

The cosine is negative in quadrants II and III, so we find
those two angles on the unit circle as 

 and 

Edwin

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SOLUTION: Find all EXACT solutions of the equation cos(x ) = &#8722;1/2 in the interval [0,2&#960;). If there is more than one answer, enter them in a list separated by commas.

SOLUTION: Find all EXACT solutions of the equation cos(x ) = −1/2 in the interval [0,2π). If there is more than one answer, enter them in a list separated by commas.