Without any information to the contrary, I'll assume that this is the pattern. So it's usually best to leave the terms in the form provided, rather than reducing them, because reducing would remove the pattern that they're wanting you to see.
I also have the alternating sign.
Other common possibilities for representation of the index are j and t. Therefore this expression means sum the values of x, starting at x1 and ending with xn. Summation notation involves: The summation sign This appears as the symbol, S, which is the Greek upper case letter, S.
To be fair, though, unless the sequence is very simple or is presented in a very straightforward manner, it is entirely possible that you might find a "wrong" pattern.
Arithmetic operations may be performed on variables within the summation. The changing numbers, as a list, start off with 6, 7, and 8. Don't let this bother you terribly much. The summation sign, S, instructs us to sum the elements of a sequence.
Arithmetic operations may be performed on expressions containing more than one variable. Then the terms seems to be in the following pattern: But how many terms are in the summation?