Editing Random walk

{{stub-general}}
Apparently, the so-called '''random walk''' problem was set out by Karl Pearson in a letter to Nature in 1905 (Ref. 1)
<blockquote> "A man starts from a point O and walks l yards in a straight line; he then turns through any angle whatever and walks another l yards in a second straight line. He repeats this process n times. I require the probability that after these n stretches he is at a distance between r and r + dr from his starting point, O."</blockquote>

==References==
#[http://dx.doi.org/10.1038/072294b0 Karl Pearson "The Problem of the Random Walk", Nature '''72''' p. 294 (1905)]
#[http://dx.doi.org/10.1038/35099646 Ian Stewart "Mathematics: Where drunkards hang out", Nature '''413''' pp. 686-687 (2001)]
[[category: polymers]]