#elisp
Function: log arg &optional base

This function returns the logarithm of arg , with base base . If you don’t specify base , the natural base e is used. If arg or base is negative, log returns a NaN

If you want to change selection, open document below and click on "Move attachment"

GNU Emacs Lisp Reference Manual: Math Functions
If the optional second argument x is given, the value of (atan y x) is the angle in radians between the vector [ x , y ] and the X axis. Function: exp arg This is the exponential function; it returns e to the power arg . <span>Function: log arg &optional base This function returns the logarithm of arg , with base base . If you don’t specify base , the natural base e is used. If arg or base is negative, log returns a NaN. Function: expt x y This function returns x raised to power y . If both arguments are integers and y is positive, the result is an integer; in this case, overflow causes tru