SOLUTION: Solve for x: 3 + cos 2x = 7/2; only include answers on [0, 2π]

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Question 1141649: Solve for x: 3 + cos 2x = 7/2; only include answers on [0, 2π]
Found 2 solutions by josmiceli, Alan3354:
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
+3+%2B+cos%28+2x+%29+=+3.5+
+cos%28+2x+%29+=+1%2F2+
The angles whose cosine = +1%2F2+ are
in the 1st and 4th quadrants.
+arc+cos+%28+1%2F2+%29+=+pi%2F3+
+arc+cos+%28+1%2F2+%29+=+5%2A%28+pi%2F3+%29+
----------------------------------
+2x+=+pi%2F3+
+x+=+pi%2F6+
and
+2x+=+5%2A%28+pi%2F3+%29+
+x+=+5%2A%28+pi%2F6+%29+

Answer by Alan3354(69443) About Me  (Show Source):
You can put this solution on YOUR website!
Solve for x: 3 + cos 2x = 7/2; only include answers on [0, 2π]
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3 + cos(2x) = 7/2
cos(2x) = 1/2
2x = pi/3, 5pi/3, 7pi/3, 11pi/3
x = pi/6, 5pi/6, 7pi/6, 11pi/6