SOLUTION: If theta is a third quadrant angle and cos theta= -2/3, find sin theta. Show work.

Question 1138392: If theta is a third quadrant angle and cos theta= -2/3, find sin theta. Show work.
Found 3 solutions by MathLover1, Alan3354, ikleyn:
Answer by MathLover1(20850)   (Show Source): You can put this solution on YOUR website!

°->theta is a third quadrant angle
then

Answer by Alan3354(69443)   (Show Source): You can put this solution on YOUR website!
If theta is a third quadrant angle and cos theta= -2/3, find sin theta.
=-------------
sin = sqrt(1 - cos^2)
sine is negative in Q3

Answer by ikleyn(52800)   (Show Source): You can put this solution on YOUR website!
.

= = = = = . The sign at the square root is " - " (MINUS), because the angle is in QIII, by the condition.

It is your standard "mantra", which you should pronounce every time, when you solve such a problem.

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