If you're going to bump questions by retagging, maybe consider simultaneously improving the titles also?
For example:
- Simplify $\sum_{i=0}^{n-1} { {2n}\choose{i}}\cdot x^i$Simplify $\sum_{i=0}^{n-1} { {2n}\choose{i}}\cdot x^i$
- Double sum involving binomial coefficients, relating to number of record lowsDouble sum involving binomial coefficients, relating to number of record lows
- Simplify an expression to show equivalenceSimplify an expression to show equivalence
- How to show $\sum_{n=0}^m \frac{1}{n+1}\binom{m}{n} = \frac{2^m-1}{m+1}$How to show $\sum_{n=0}^m \frac{1}{n+1}\binom{m}{n} = \frac{2^m-1}{m+1}$
- Compute $\sum_0^{n-1}2^i11^{n-i-1}\bmod10^9$ when $n=13^{17}$Compute $\sum_0^{n-1}2^i11^{n-i-1}\bmod10^9$ when $n=13^{17}$
- How can I simplify this expression involving binomial coefficients?How can I simplify this expression involving binomial coefficients?
- How to simplify or calculate a formula with very big factorialsHow to simplify or calculate a formula with very big factorials
Probably in all of these these cases, the title would benefit from simple copy/pasting the sum into the title.
