Log Function

Log()`number`

`number`

Use: Required

Data Type: Double

A numeric expression greater than zero.

A Double.

Returns the natural logarithm of a given number.

The natural logarithm is based on

, a constant whose value is approximately 2.718282. The natural logarithm is expressed by the equation:`e`

e

^{z}= xwhere

`z`

`=`

`Log(x)`

. In other words, the natural logarithm is the inverse of the exponential function., the value whose natural logarithm the function is to return, must be a positive real number. If number is negative or zero, the function generates runtime error 5, “Invalid procedure call or argument.”`number`

You can calculate base-

logarithms for any number`n`

, by dividing the natural logarithm of`x`

by the natural logarithm of`x`

, as the following expression illustrates:`n`

Log

(`n`

) = Log(`x`

) / Log(`x`

)`n`

For example, the

*Log10*function shows the source code for a custom function that calculates base-10 logarithms:Function Log10(X) Log10 = Log(X) / Log(10) End Function

A number of other mathematical functions that aren’t intrinsic to VBScript can be computed using the value returned by the

*Log*function. The functions and their formulas are:- Inverse Hyperbolic Sine
`HArcsin(X)`

`=`

`Log(X`

`+`

`Sqr(X`

`*`

`X`

`+`

`1))`

- Inverse Hyperbolic Cosine
`HArccos(X)`

`=`

`Log(X`

`+`

`Sqr(X`

`*`

`X`

`-`

`1))`

- Inverse Hyperbolic Tangent
`HArctan(X)`

`=`

`Log((1`

`+`

`X)`

`/`

`(1`

`-`

`X))`

`/`

`2`

- Inverse Hyperbolic Secant
`HArcsec(X)`

`=`

`Log((Sqr(-X`

`*`

`X`

`+`

`1)`

`+`

`1)`

`/`

`X)`

- Inverse Hyperbolic Cosecant
`HArccosec(X) ...`

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