"Mathieu Bouchard" <matju / sympatico.ca> schrieb im Newsbeitrag news:Pine.LNX.4.21.0503262110380.5161-100000 / mondrian.artengine.ca... > > On Fri, 18 Mar 2005, Phrogz wrote: >> Aside - whatever the name, what an excellent, versatile function! For >> example, the linked-to geometric series sum at >> http://www.brpreiss.com/books/opus8/programs/pgm02_06.txt can be >> written in a more terse and (IMO) more ruby-esque way as simply: >> def geometric_series_sum( x, n ) >> (0..n).inject(0){ |sum,i| sum+x**i } >> end > > And even shorter, > > def geometric_series_sum(x,n) (x**(n+1)-1)/(x-1) end LOL ... and more efficient also. Know your math. :-) Cheers robert