how to find equation of polynomial from a graph

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- Sep 16th 2007, 05:01 AMsupersaiyanhow to find equation of polynomial from a graph
how to find equation of polynomial from a graph

- Sep 16th 2007, 05:24 AMtopsquark
That depends. Do you have the graph to show us?

A polynomial of degree n can always be expressed as

$\displaystyle f(x) = a(x - r_1)(x - r_2)...(x - r_n)$

where the r's are the x-intecepts of the graph. The problem is that roots are not always real, and thus do not show up on the graph.

It would be best if you showed us your problem so we could tell you what cases you need to consider, etc.

-Dan - Sep 16th 2007, 07:04 AMThePerfectHacker
You can also pick (n+1) points (assuming you know its degree at least) and create a system of equations and solve them. (Which is extremely messy in general but it always works).