The ramp region shrinks but never disappears only an interval with a fixed gap from 0 can outrun it

For each positive integer n, let $f_{n}:[-1,1]\to\mathbb{R}$ be given by $f_{n}(x)=-1$ if $-1\le{}x\le-1/n, f_{n}(x)=$nx if −1/n<x<1/n, and $f_{n}(x)=1$ if 1/n≤x≤1. On which of the following intervals does the sequence {$f_{n}$}$_{n}\ge1$ converge uniformly?