00:02
So in this problem, we're looking for the equation of three different parabolas.
00:17
And the first one, we're given that the vertex is at the origin, and the directics, is y equals a half.
00:35
Remember, the directrix is the line that goes through the focus for the focus point, for the parabola.
00:53
So with this information, what we know is that the equation of this parabola follows the form x squared equals minus 4 a y, where y equals a is the equation of the directics.
01:21
So that means i have x squared equals minus 4 times.
01:25
Times a half times y.
01:30
Well, two goes into four twice, so this is minus two, y.
01:36
It's equal to, of course, x squared...