Question

what kind of function best models the data in the table use differences and ratios.

x y
0 4
1 5
2 8
3 13
4 20

Answer 1

differences:
1 3 5 7
2 2 2

so, the function is a quadratic

Answer 2

x y 1stdiff -- 2nddiff
0 4
1 5 -- 1 -----
2 8 -- 3 ----- 2
3 13 --5 ----- 2
4 20 --7 ----- 2

since the 2nd difference is a constant, it must be a quadratic, or 2nd degree function

Answer 3

Ok thank you!