@defun log number &optional base
This function returns the logarithm of @var{number}, with base @var{base}.
-If you don't specify @var{base}, the base @var{e} is used. If @var{number}
+If you don't specify @var{base}, the base @code{e} is used. If @var{number}
is negative, the result is a NaN.
@end defun