23 March 2018

NaN

NaN is an acronym for Not a Number used in computing and represents a value or a symbol that is usually produced as a result of an invalid operation on the operands. NaNs are close to some undefined or indeterminate expressions in mathematics. The NaN is not really a number, but a symbol that represents a numerical quantity whose absolute value can not be determined by the Operating System.

Examples:

• $\sqrt {-1}$;
• $\log(-n)$ and $\ln(-n)$;
• $\frac{0}{0}$;
• $0^0$;
• $1^\infty$;
• $\infty^0$;
• $\frac{\infty}{\infty}$, $\frac{\infty}{-\infty}$, $\frac{-\infty}{\infty}$ and $\frac{-\infty}{-\infty}$;
• $0 \times \infty$ and $0 \times (-\infty)$;
• $(-\infty) + \infty$ and $\infty + (-\infty)$;
• $\ln |0|$ and $\frac{\ln |0|}{\ln |\pm \infty|}$;
• $e^{\pm \infty} \times \log |0|$;
• $\frac{m}{\pm \infty} \times \frac{n}{0}$ if $m \neq \pm \infty$ and $n \neq 0$.