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| Question 131065:  Hello,
 I am having a hard time understanding the concept of even and odd Trigonometric Functions and have come to a problem I just do not understand how to solve.  The problem is:
 Use the even-odd properties to find the exact value of the expression. It may be helpful to draw the unit circle graph. I can input this into a calculator to get the answer, but I need to learn and understand for future studies.
 sin(-pi)
 
 Any help or explanation in layman's terms would be appreciated. Thanks so much!
 Answer by stanbon(75887)
      (Show Source): 
You can put this solution on YOUR website! sin(-pi) ------------
 Draw the unit circle on a coordinate system.
 Four points on the circle:
 At 0 radians you have (1,0)
 At pi/2 you have (0,1)
 At pi you have (-1,0)
 At (3/2)pi you have (0,-1)
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 The point (-1,0) is at pi radians and at -pi radians.
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 The y-value for each of these points (and all other points
 on the circle, is the sine of the corresponding angle.
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 So, sin(-pi) = 0
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 Cheers,
 Stan H.
 
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