SOLUTION: Please help me solve this problem. Please list the answers from all applicable quadrants. {{{ cos x = -sqrt(3)/2 }}}

Algebra ->  Trigonometry-basics -> SOLUTION: Please help me solve this problem. Please list the answers from all applicable quadrants. {{{ cos x = -sqrt(3)/2 }}}      Log On


   

Question 1058898: Please help me solve this problem. Please list the answers from all applicable quadrants. +cos+x+=+-sqrt%283%29%2F2+
Found 2 solutions by ikleyn, josmiceli:
Answer by ikleyn(52781) About Me  (Show Source):
You can put this solution on YOUR website!
.
x = 5pi%2F6 = 150 degrees in QII, and

x = 7pi%2F6 = 210 degrees in QIII.


You need to learn (to know) what is the trigonometric function cosine.


Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
The cosine function is negative in the
2nd and 3rd quadrants
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In the 2nd quadrant, the angle is
+pi+-+pi%2F6+=+%28+5%2Api+%29%2F6+ or +150+ degrees
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In the 3rd quadrant, the angle is:
+pi+%2B+p%2F6+=+%28+7%2Api+%29%2F6+ or +210+ degrees
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So, +x+=+%28+5%2Api+%29%2F6+ and +%28+7%2Api+%29%2F6+