Determine the exact values of cos(13pi/12).....
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Originally Posted by polymerase Determine the exact values of cos(13pi/12)..... HINT: Use half-angle formula. EDIT: Mistake fixed.
Last edited by ThePerfectHacker; August 26th 2007 at 12:05 PM.
Originally Posted by polymerase Determine the exact values of cos(13pi/12)..... Now use the half angle formula for cosine. Note that is in the third quadrant, so the answer is negative
Last edited by Jhevon; August 26th 2007 at 11:02 AM. Reason: silly mistake. i said the angle was in the wrong quadrant, fixed it
Now use
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