BIGpedia - Defined and undefined - Encyclopedia and Dictionary Online

(Redirected from Undefined)

In mathematics, defined and undefined are used to explain whether or not expressions have meaningful, sensible output. These are also known as "well-behaved" and respectively "ill-behaved".

The following algebraic expressions are undefined:

$\frac{x}{0}$ (see division by zero)
$\sqrt[0]{x}$ (since $\sqrt[n]{x} = x ^ {1 \over n}$ )
$00$
$\infty - \infty$
$0 \cdot \pm\infty$
$\frac{\pm\infty}{\pm\infty}$

Undefined values of a function are usually determined by the limit of the function as it approaches the singularity.

Categories: Mathematical terminology