← bentsa.eu
∑
UniComp
Browse
Competitions
Results
About
☾
IMC
/
1994
/
Day 2, Problem 6
IMC 1994 · Problem 6
Day 2
22 points
1st IMC · Plovdiv, Bulgaria
Statement
Find
lim
N
→
∞
ln
2
N
N
∑
k
=
2
N
−
2
1
ln
k
⋅
ln
(
N
−
k
)
.
\lim_{N \to \infty} \frac{\ln^2 N}{N} \sum_{k=2}^{N-2} \frac{1}{\ln k \cdot \ln(N-k)}.
N
→
∞
lim
N
ln
2
N
k
=
2
∑
N
−
2
ln
k
⋅
ln
(
N
−
k
)
1
.
Note that
ln
\ln
ln
denotes the natural logarithm.
Official solution
Reveal
Hidden so you can work on the problem first.
Previous
Day 2 · Problem 5