2006 iTest Problems/Problem 9
Revision as of 12:57, 28 November 2018 by Rockmanex3 (talk | contribs) (Solution to Problem 9 -- Sines and Cosines)
Problem
If and is in the third quadrant, what is the absolute value of ?
Solution
Since is in the third quadrant, is negative, so . Using the half-angle identity (or the double angle cosine identity), The answer is .
See Also
2006 iTest (Problems, Answer Key) | ||
Preceded by: num-b=8 |
Followed by: Problem 10 | |
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