IMO Shortlist 1991 problem 10


Kvaliteta:
  Avg: 0.0
Težina:
  Avg: 0.0
Dodao/la: arhiva
April 2, 2012
LaTeX PDF
Prove that \sum_{k = 0}^{995} \frac {( - 1)^k}{1991 - k} {1991 - k \choose k} = \frac {1}{1991}
Source: Međunarodna matematička olimpijada, shortlist 1991