The SUMX2PY2 function returns the sum of the sum of squares of corresponding values in two arrays. The "p" in the function name stands for "plus", as in "sum x2plus y2".
SUMX2PY2 takes two arguments, array_x and array_y. Array_x is the first range or array or range of numbers, and array_y is the second range or array of numbers. Both arguments can be provided as an array constant or as a range.