Question

(1-1supra2) ori (1 -1supra3) ori (1-1supra4). Ori ( 1-1supra2011)
Va rog mult am nevoie acum dau coroana.

Answer 1

$1-\frac{1}{2} =\frac{1}{2} \\\\1-\frac{1}{3} =\frac{2}{3} \\\\1-\frac{1}{4} =\frac{3}{4}\\\\ ...\\1-\frac{1}{2011} =\frac{2010}{2011}$

se reduc pe diagonala 2 cu 2, 3 cu 3, 4 cu 4,..... 2010 cu 2010

$P=\frac{1}{2011}$