What is the question?
Are we expected to expand it?
. . . . . . . .
Ok Thank you! i was looking at another double summation:
Σ Σ Xij
The expansion in my text is as follows:
^i dont understand why the x13 is used because i is only 1 to 2...
can you explain the x13 in parenthesis and explain the expansion I think i may have missed something.