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Question 698401: determine the orientation of the parabola.
directrix: x= -3; p= 4
a.opens down c.opens up
b.opens right d.opens left
Answer by Positive_EV(69)   (Show Source):
You can put this solution on YOUR website! The directrix determines whether the parabola opens up/down or left/right. In this case, the parabola has a directrix in the form x = a, meaning it will open to the left or right. (A parabola with a directrix in the form y = a opens up or down).
Next, look at the sign of p. Since p is positive, the parabola opens to the right (if p were less than zero, it'd open to the left).
Incidentally, if the directrix were in the form y = a and the parabola opened up or down, a p value that is positive indicates the parabola opens up, and a p value that is negative indicates the parabola opens down.
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