Thread: double summations:

n m
Σ Σ Xij
i=1 j=1

Hello, nassaufashionista!

What is the question?

Are we expected to expand it?



. . . . . . . .

Ok Thank you! i was looking at another double summation:

2 3
Σ Σ Xij
i=1 j=1

The expansion in my text is as follows:
(x11+x12+{x13}+x21+x22+x23
^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.