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View Full Version : Maths parabolas


miszak
Jun 9, 2012, 07:35 AM
Find the focus and directrix and then draw graph of
x^2=-7y

ebaines
Jun 11, 2012, 02:14 PM
Find the focus and directrix and then draw graph of
x^2=-7y

You need to rewrite the equation into the standard form, which is:


y-y_0 = \pm \frac {1 }{4p} (x-x_0)^2


and then the point (x_0, y_0) is the vertex of the paraola, the focus is distance p from the vertex towards the inside of the parabola, and the directrix is a line located distance p from the vertex towards the outside of the parabola.