Example · High school

Terms

TermThis exampleWhy
limit (of a function) $\lim_{x \to 0} f(x) = 1$ $f(0)$ is undefined, but the limit exists anyway.
left limit $\lim_{x \to 0^{-}} f(x) = 1$
right limit $\lim_{x \to 0^{+}} f(x) = 1$ $\frac{\sin x}{x}$ approaches $1$ from both sides of $0$, so the left limit, the right limit, and the limit are all $1$, even though $f(0)$ is undefined.
continuous ✗ The function is not continuous at $x = 0$ because $f(0)$ is undefined, so $x = 0$ is not in the domain of $f$.

All examples · All distinctions · All definitions