When the x's are equally spaced, the calculation of
and
can be simplified by coding the x's by assigning them the values ... , -3, -2, -1, 0, 1, 2, 3, ... when n is odd, or the values ... , -5, -3, -1, 1, 3, 5, ... when n is even. Show that with this coding the formulas for
and
become
![](https://test.transtutors.com/qimg/13ff1daa-b488-4942-a84d-9da4556737be.png)