(log number)

Calculate the natural logarithm.

This function returns the natural logarithm, even though "ln" is usually considered the natural log in mathematics. This function cannot take a negative number. The result is a real number.

Examples

Code	Returns
(log 0)	1.000000
(log 9)	2.19722
(log 10)	2.30239
(log 2.30239)	0.834035

NOTE The exp function is the opposite of the log function.

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(expt base power)

(log10 number)

LISP Compatibility

Programming Overview of LISP (LISt Processing) Language