Answers

2015-05-06T12:18:00+05:30
\sum\limits_{n=0}^N2^n~~=~~2^0+2^1+2^2+\cdots+2^N

This is a geometric series with common ratio = 2 and it has N+1 terms.
Using partial sum formula, the sum equals :
=\frac{2^{N+1}-1}{2-1}

=2^{N+1}-1
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