<PRE><B>Question 212525</B>
Give the exact value of the following. If it is undefined, so state. 
1)tan 4pi/3
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(4/3)pi is 60 degrees in the 3rd quadrant
tan[(4/3)pi] = -sqrt(3)
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2)sin 120 degrees
120 has a reference angle of 60 degrees in the 2nd quadrant
sin(120) = sqrt(3)
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3)cos 5pi/6 
(5/6)pi has a reference angle of 30 degrees in the 2nd quadrant:
cos[(5/6)pi] = -cos(30) = -sqrt(3)/2
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Cheers,
Stan H.</PRE>