Problem

Source: Kvant Magazine No. 9 2019 M2575

Tags: algebra, polynomial, Kvant



Let $t\in (1,2)$. Show that there exists a polynomial $P(x)=a_nx^n+a_{n-1}x^{n-1}+...+a_1x+a_0$ with the coefficients in $\{1,-1\}$ such that $\left|P(t)-2019\right| \leqslant 1.$ Proposed by N. Safaei (Iran)