Difference between revisions of "2006 iTest Problems/Problem 9"
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==See Also== | ==See Also== | ||
− | {{iTest box|year=2006| | + | {{iTest box|year=2006|num-b=8|num-a=10|ver=[[2006 iTest Problems/Problem U1|U1]] '''•''' [[2006 iTest Problems/Problem U2|U2]] '''•''' [[2006 iTest Problems/Problem U3|U3]] '''•''' [[2006 iTest Problems/Problem U4|U4]] '''•''' [[2006 iTest Problems/Problem U5|U5]] '''•''' [[2006 iTest Problems/Problem U6|U6]] '''•''' [[2006 iTest Problems/Problem U7|U7]] '''•''' [[2006 iTest Problems/Problem U8|U8]] '''•''' [[2006 iTest Problems/Problem U9|U9]] '''•''' [[2006 iTest Problems/Problem U10|U10]]}} |
[[Category:Introductory Trigonometry Problems]] | [[Category:Introductory Trigonometry Problems]] |
Revision as of 20:56, 28 November 2018
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: Problem 8 |
Followed by: Problem 10 | |
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