CommandslogOn this pagelog log (num) The log function returns the log base 10 of num. It returns -INF if num is 0, and returns NaN if num is less than 0. To compute a logarithm base n use the formula: logn(x)=log(x)log(n).\displaystyle \log _{n}(x)=\frac{\log (x)}{\log (n)}.logn(x)=log(n)log(x). See Also ln