Plot the points (scatter plot?)

Find quadratic function that best models:

(-4,37)

(-3,19)

(-2,7)

(-1,1)

(0,1)

(1,7)

(2,19)

Do I use my calculator? If so, how?

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- Mar 23rd 2009, 04:05 PMkcwillia377How do you find a quadratic function?
Plot the points (scatter plot?)

Find quadratic function that best models:

(-4,37)

(-3,19)

(-2,7)

(-1,1)

(0,1)

(1,7)

(2,19)

Do I use my calculator? If so, how? - Mar 23rd 2009, 04:18 PMe^(i*pi)
As you have the point (0,1) you know it will be $\displaystyle y = ax^2+bx+1

$

Now you can do $\displaystyle 1 = a -b$, $\displaystyle a = 1+b$ and $\displaystyle 7 = a + b$

7 = (1+b)+b , 2b+1 = 7 and so b = 3

Therefore a is 7 = a+3 and so a = 4

Putting all these together we get:

4x^2 + 3x + 1 = 0