Thread: finite differences to find out if it is linear or quadratic

how do you use finite differences to determine whether relation is quadratic or linear?


X, Y FIRST DIFFERENCE

(1,-33) -

(2,-31) 2

(3,-27) 4

(4,-20) 7

(5,-9) 11



Is this relation linear, quadratic OR neither and why?

2nd differences are 2 , 3 , 4

3rd differences are a constant 1

it's cubic ...