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
