SOLUTION: I want to know how you workout the eqaution for a parabola line but the vertex isn't on the y-axis and how to change the width of the line. Thank in advanced.

Algebra ->  Coordinate Systems and Linear Equations  -> Lessons -> SOLUTION: I want to know how you workout the eqaution for a parabola line but the vertex isn't on the y-axis and how to change the width of the line. Thank in advanced.      Log On


   

Question 912790: I want to know how you workout the eqaution for a parabola line but the vertex isn't on the y-axis and how to change the width of the line. Thank in advanced.
Found 2 solutions by josgarithmetic, josmiceli:
Answer by josgarithmetic(39617) About Me  (Show Source):
You can put this solution on YOUR website!
Parabola? What line? Which line, where? Lines do not have width.

Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
You can move the parabola either right
or left by writing equation as:
+y+=+%28+x+-+a+%29%5E2+
+y+=+x%5E2+-+2ax+%2B+a%5E2+
-------------------
Notice that +y+=+0+ when
+0+=+%28+a+-+a+%29%5E2+
The vertex is at (a,0)
------------------
This is how you move the vertex from
(0,0) to anywhere on the x-axis
-----------------------------
Then, in order to move up or down,
you need:
+y+=+%28+x-a+%29%5E2+%2B+b+
----------------------
To make the parabola narrower ( skinny ),
+y+=+c%2A%28+x-a+%29%5E2+%2B+b+
where +c%3E1+
To make the parabola wider ( fatter ),
+c+%3C1+
------------
Say
+a+=+3+
+b+=+5+
+c+=+1+
---------------
A 2nd parabola is:
+a+=+3+
+b+=+-5+
+c+=+4+
Here are the plots:

The skinnier one is:
+y+=+4%2A%28+x-3+%29%5E2+-+5+
Hope this helps