The series is finite if the number of terms or the last term is given.
If a summation sign is used, the limit of the summation is infinity for an infinite series.
1 + 2 + 4 + 8 + ... . . . . . is an infinite series. It has no last term.
[tex]=\sum\limits_{n=1}^{\infty} 2^{n-1}[/tex]
1 + 2 + 4 + 8 + ... + 1024 . . . . . is a finite series. The last term is given.
The upper limit on the summation symbol is a finite number.
[tex] = \sum\limits_{n=1}^{11} 2^{n-1}[/tex]
