## Calculus 8th Edition

continuous on $(-\infty, \infty)$
$F(x)=\displaystyle \frac{2x^{2}-x-1}{x^{2}+1}$ is a rational function. Its domain is $(-\infty, \infty)$ (no x yields zero in the denominator). By theorem 5 (b) Any rational function is continuous wherever it is defined; that is, it is continuous on its domain.