Question 912213: Let P(t) be the point on the unit circle U that corresponds to t. If P(t) = (15/17, 8/17), find the following.
P(t+pi)=( ? , ? )
P(t-pi)=( ? , ? )
P(-t)=( ? , ? )
P(-t-pi)=( ? , ? )
Answer by jim_thompson5910(35256)   (Show Source):
You can put this solution on YOUR website! (15/17, 8/17) is in quadrant I
Adding pi to the angle rotates it 180 degrees to quadrant III where both x and y are negative, so
P(t+pi)=(-15/17, -8/17)
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The same thing happens when you subtract pi because you will land in the same place rotating 180 degrees CCW or CW
P(t-pi)=(-15/17, -8/17)
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P(-t) = (15/17, -8/17)
because you go below the x axis when you have a negative angle
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Take the angle -t and rotate it 180 degrees. You'll go from Q4 to Q2
So x is negative, y is positive
P(-t-pi) = (-15/17, 8/17)
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