Question 80220: If csc theta=-5/4 and theta is in quadrant 3,then cos theta=
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! If csc theta=-5/4 and theta is in quadrant 3,then cos theta=?
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Draw the picture of theta in the 3rd quadrant.
csc(theta)=r/y
The terminal side passes thru the point (x,-4) and r=5.
Find x where x^2+y^2=r^2
x^2=5^2-4^2=9
x=-3 in the 3rd Quadrant
Therefore cos(theta)= x/r=-3/5
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Cheers,
Stan H.
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