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April 18, 2014

April 18, 2014

Posted by **sam** on Thursday, November 11, 2010 at 4:40pm.

cot[arccos(-2/3)]

- trigonometry -
**MathMate**, Thursday, November 11, 2010 at 4:52pmcos(θ)=-2/3

So θ is in the second or third quadrant. There is not enough information to be sure of which.

adjacent = -2

hypotenuse = 3

opposite = ±√(3²-(-2)²)

= ±√(5)

Therefore

cot(θ)

=adjacent/opposite

=-2/(±√(5))

= ±(2/√(5))

=±(2√(5)/5)

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