Guichard-Combinatorics-Graph-Theory · Problem 1.3.12

Fundamentals

Mathematics — Probability · binomial-coefficients

Problem

Use (x+1)n=∑i=0n(ni)xi(x+1)^n = \sum_{i=0}^{n} \binom{n}{i} x^i to find a simple expression for ∑i=0n1i+1(ni)xi+1\sum_{i=0}^{n} \frac{1}{i+1} \binom{n}{i} x^{i+1}. Then find a simple expression for ∑i=0n1i+1(ni)\sum_{i=0}^{n} \frac{1}{i+1} \binom{n}{i}.

Related theory

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