AoPS Wiki talk:Problem of the Day/June 17, 2011

Revision as of 21:58, 16 June 2011 by Djmathman (talk | contribs) (No need for {{potd_solution}})

Problem

AoPSWiki:Problem of the Day/June 17, 2011

Solution

$\frac{1^{3}+2^{3}+3^{3}+...+x^{3}}{1+2+3+...+x}=\frac{(1+2+3+...+x)^2}{1+2+3+...+x}=1+2+3+...+x$


$1+2+3+...+x=\frac{x\cdot(x+1)}{2}$ Subbing in the value of $x$ we get,$\frac{9001\cdot9002}{2}=\boxed{40513501}$