Template:Log

The following documentation is located at Template:Log/doc. [<Edit> Template:Log/doc]
[⧼Purge⧽ Template:Log]

The {{log}} (alternatively {{log_e}} or {{ln}}) mathematical function template returns the natural logarithm of $\scriptstyle x\,$, where $\scriptstyle x\,$ is a positive real number.

You may also use ln with the parser function extension #expr:, e.g.

{{#expr: ln 15 }} giving 2.7080502011022

Usage

{{log|a positive real number}}

or

{{log_e|a positive real number}}

or

{{ln|a positive real number}}

Valid input

A positive real number as argument.

Examples

Examples with valid input

Code	Result
{{ln|e^(-1)}}	-1
{{ln|e^(-0.5)}}	-0.5
{{ln|0.5}}	-0.69314718055995
{{log|1}}	0
{{ln|1.5}}	0.40546510810816
{{ln|e^({{phi}})}}	1.6180339887499
{{log_e|10}}	2.302585092994
{{ln|1.5*e^4}}	4.4054651081082
{{log|1000}}	6.9077552789821
{{log|e^40}}	40
{{log|e^25 * e^40}}	65

Examples with invalid input (returns an error message)

Code	Result
{{log|i}}
{{log|-1}}
{{log|0}}

Code

<noinclude>{{documentation}}</noinclude><includeonly>{{ifnum| {{{1|NaN}}}
| {{#ifexpr: ( {{{1}}} ) > 0
  | {{#expr: ln ( {{{1}}} ) }}
  | {{error| Log error: Argument must be a positive real number }}
  }}
| {{error| Log error: Argument must be a positive real number }}
}}</includeonly>

See also

• {{log}} or {{log_e}} or {{ln}}
• {{log_2}}
• {{log_10}}
• {{log_b}}