MathDB
A nice identity concerning an integral and a serie

Source: Brazilian Math Olympiad 2005, Problem 5

October 24, 2005
calculusintegrationlogarithmsfunctioninductionreal analysisreal analysis solved

Problem Statement

Prove that n=11nn=01xxdx. \sum_{n=1}^\infty {1\over n^n} = \int_0^1 x^{-x}\,dx.