# Its here again

Calculus Level 4

$\sum_{n=0}^{\infty} \binom{2n}{n}x^{n}$

If the above sum is a real number, find $$\displaystyle \sup x - \inf x$$, where $$\sup$$ is the supremum, $$\inf$$ is the infimum, and $$x$$ is real.

×