MathDB
Problems
Contests
National and Regional Contests
Ireland Contests
Ireland National Math Olympiad
2015 Irish Math Olympiad
10
binomial inequality, with pairs of nonnegative integers
binomial inequality, with pairs of nonnegative integers
Source: Irmo 2015 p2 q10
September 16, 2018
Binomial
inequalities
Binomial summation
Inequality
Problem Statement
Prove that, for all pairs of nonnegative integers,
j
,
n
j,n
j
,
n
,
∑
K
=
0
n
k
j
(
n
k
)
≥
2
n
−
j
n
j
\sum_{K=0}^{n}k^j\binom n k \ge 2^{n-j} n^j
K
=
0
∑
n
k
j
(
k
n
)
≥
2
n
−
j
n
j
Back to Problems
View on AoPS