Question 400901: graph the equation. identify the focus and directrix of the parabola, y^2=-4x
Answer by lwsshak3(11628)   (Show Source):
You can put this solution on YOUR website! graph the equation. identify the focus and directrix of the parabola, y^2=-4x
..
y^2=-4x is of the form, y^2=-4px
This is a parabola with horizontal axis of symmetry,y=0, opening leftward.
vertex (0,0)
4p=4
p=1
..
The focus is on the line of symmetry so its y-coordinate=0
Its x-coordinate is "p" or 1 unit to the left of the vertex.
Therefore, the (x,y) coordinates of the focus is (-1,0)
..
The directrix is a vertical line "p" or 1 unit on the right side of the vertex, that is, x=1
..
ans: The focus is at (-1,0), and equation of the directrix is x=1
see the following graph
|
|
|
