MathDB
Choosing signs for sum of squares

Source: Baltic Way 2009

December 4, 2009
algebrapolynomialnumber theory proposednumber theory

Problem Statement

Let n n be a given positive integer. Show that we can choose numbers c_k\in\{\minus{}1,1\} (i≤k≤n i\le k\le n) such that 0\le\sum_{k\equal{}1}^nc_k\cdot k^2\le4.
Back to ProblemsView on AoPS