# Math.log()

La función Math.log() devuelve la base neutral de un número (base e)

$∀ x > 0 , Math.log ( x ) = ln ( x ) = the unique y such that e y = x \forall x > 0, \mathtt{\operatorname{Math.log}(x)} = \ln(x) = \text{el unico} ; y ; \text{tal que} ; e^y = x$

La función en JavaScrcrip Math.log() es equivalente a ln(x) en matematicas.

## Sintaxis

Math.log(x)


### Parametetros

x

Es un numero.

### Retorna el valor

La base natural (base e) del número dado. Si el número es negativo, se devuelve NaN

## Descripcion

If the value of x is negative, the return value is always NaN.

Because log() is a static method of Math, you always use it as Math.log(), rather than as a method of a Math object you created (Math is not a constructor).

If you need the natural log of 2 or 10, use the constants Math.LN2 or Math.LN10 . If you need a logarithm to base 2 or 10, use Math.log2() or Math.log10() . If you need a logarithm to other bases, use Math.log(x) / Math.log(otherBase) as in the example below; you might want to precalculate 1 / Math.log(otherBase) .

## Examples

### Using Math.log()

js
Math.log(-1); // NaN, out of range
Math.log(0); // -Infinity
Math.log(1); // 0
Math.log(10); // 2.302585092994046


### Using Math.log() with a different base

The following function returns the logarithm of y with base x (ie. $\log_x y$):

js
function getBaseLog(x, y) {
return Math.log(y) / Math.log(x);
}


If you run getBaseLog(10, 1000) it returns 2.9999999999999996 due to floating-point rounding, which is very close to the actual answer of 3.

## Especificaciones

Specification
ECMAScript Language Specification
# sec-math.log