Find expressions for the quadratic functions whose graphs are shown:

http://img204.imageshack.us/img204/8...aticqv3.th.png

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- Jan 31st 2009, 05:40 PMquestion111Find expressions for the quadratic functions
Find expressions for the quadratic functions whose graphs are shown:

http://img204.imageshack.us/img204/8...aticqv3.th.png - Jan 31st 2009, 05:44 PMJhevon
there are several ways to approach this. here's one

note that the vertex is on the x-axis, that is, we have a double root for the vertex

thus, our quadratic is of the form $\displaystyle y = a(x - 3)^2$

we are given that the point (4,2) is on the graph, we can use this to find $\displaystyle a$, by plugging in $\displaystyle x = 4$ and $\displaystyle y = 2$ into the form above

what is your answer? - Jan 31st 2009, 05:50 PMShyam
- Jan 31st 2009, 05:51 PMJhevon
- Feb 1st 2009, 02:38 PMquestion111
So a would be 2, and when I plug that in, I am finally getting a graph like it's shown in the book.

Thank you very much. - Feb 1st 2009, 03:11 PMJhevon
- Jan 24th 2010, 10:48 PMlovegreenand so what is your expression
(Thinking)

- Jan 24th 2010, 10:54 PMJhevon
- Jan 25th 2010, 12:32 AMlovegreenThanks!
I see it is y = 2(x squared) -12x + 18

- Jan 25th 2010, 03:43 AMHallsofIvy