Closed form of $\sum_{i=0}^n ia^i$ derivation
562
Formula for calculating $\sum_{n=0}^{m}nr^n$
47670
Algebraic proof of $\sum_{i=0}^k{{n \choose i}{m \choose {k-i}}}= {{m+n}\choose k}$
117200
Evaluation of $ \sum_{k=0}^n \cos k\theta $
97266
Summation by parts (finite calculus) of $\sum\limits_{i=0}^{n}i\cdot a^i$
151757
Simplify $\sum_{i=0}^{N/2}{N-i\choose i}$
58972
Proof/Derivation of Closed form of Binomial Expression $\sum\limits_{k=0}^{2n}(-1)^k\binom{2n}{k}^2$
48200
Simplify $\sum_{i=0}^n (i+1)\binom ni$
65653
Find a closed form of the series $\sum_{n=0}^{\infty} n^2x^n$
119606
Closed form of summation
5537
Closed form for $ \int_0^\infty {\frac{{{x^n}}}{{1 + {x^m}}}dx }$
19914
Closed form for $\sum_{n=0}^{\infty} \binom{n+k}{k} x^n$ (Negative Binomial Theorem)
87479
Closed form for $\sum_{k=0}^{n-p}\binom{n}{k}\binom{n}{p+k}$
127284
Closed form of $\int_0^{\pi/2} \frac{\arctan^2 (\sin^2 \theta)}{\sin^2 \theta}\,d\theta$
133905
Intuitive proof of $\sum_{k=1}^{n} \binom{n}{k} k^{k-1} (n-k)^{n-k} = n^n$
156597
Proving a reduction formula for the antiderivative of $\cos^n(x)$
45725
Derivation of an identity with beta function.
94627
What's wrong with this derivation that $i\hbar = 0$?