Positively non-positive
Algebra
Level
5
For how many positive integers \( N \) between 3 and 1000 (inclusive) is the following statement true?
If \( \{ a_i \} _{i=1}^N\) is a set of \(N\) (not necessarily distinct) real numbers such that
\[ a_1 + a_2 + \cdots + a_N = 0, \]
then we must (always) have
\[ a_1 a_2 + a_2 a_3 + \ldots + a_{N-1} a_N + a_N a_1 \leq 0. \]
\[\] Clarification: The cases of \(N=1, N=2 \) are removed to avoid ambiguity in the second summation.
by
Calvin Lin