Tables

First Difference

When looking at a table of values, the "finite differences" can be used to find the degree of a polynomial and then write a function rule. When looking at linear equations, the finite difference is called the "first difference." The first difference is the difference in y values of a given function. If the difference between each y value is constant, the function will be linear.

The formula y = ax + b is used to write a function rule using first difference. Where "a" corresponds to the value of the first difference and b is the y-intercept, (0, b).