X is any expression producing a value for each
element in i.
i is a range
of integers. The acceptable range depends on the size of X and the ORIGIN of the worksheet.
Notes:
Define the range
variablei before using the sum with range
variable operator. To include the range variable as part of the operator,
use the product without
range variables operator.
If X has several terms, be
sure to enclose them in parentheses to keep them inside the product operator.
Under symbolic evaluation, if no range is specified,
results are typically based on ranges which start at 0 or 1.