SOLUTION: Find the vertex, focus and directrix of the parabola given by the equaiton (y + 2)^2 + -4(x-1)

Algebra ->  Trigonometry-basics -> SOLUTION: Find the vertex, focus and directrix of the parabola given by the equaiton (y + 2)^2 + -4(x-1)      Log On


   

Question 857859: Find the vertex, focus and directrix of the parabola given by the equaiton (y + 2)^2 + -4(x-1)
Answer by KMST(5328) About Me  (Show Source):
You can put this solution on YOUR website!
You are missing something. There should be an equal sign somewhere.
Maybe you meant to type
(y + 2)^2 = -4(x-1) and got a + sign instead of the intended = sign.

%28y+%2B+2%29%5E2+=+-4%28x-1%29<-->-%281%2F4%29%28y+%2B+2%29%5E2+=+%28x-1%29
is the equation of a parabola with a horizontal axis of symmetry,
y%2B2=0<-->y=-2 ,
and the vertex at (1,-2).
The focal distance is 1 ,
and the focus and the rest of the parabola are to the left.
So the focus is at (0,-2),
1 unit to the left of (1,-2),
and the directrix is the line x=2 ,
1 unit to the left of (1,-2).