You would know that
[tex]\displaystyle\lim_{x\to\pm1}f(x)=1[/tex]
It follows from the sandwich/squeeze theorem: for instance,
[tex]x^4 \le f(x) \le x^2 \implies \displaystyle\lim_{x\to-1}x^4 \le \lim_{x\to-1}f(x) \le \lim_{x\to-1}x^2 \implies 1 \le \lim_{x\to-1}f(x) \le 1 \\\\ \implies \lim_{x\to-1}f(x)=1[/tex]