Why does JavaScript Math.log(1.001) return the wrong value?

JavaScript returns .0009995003330834232.

Every other way of calculating re开发者_StackOverflowturns 0.000434077479319.

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It returns the natural logarithm, i.e. the logarithm to base e = 2.71828..., instead of the logarithm to base 10.

log_e(1.001) = 0.00099950033308342321
log_10(1.001) = 0.0004340774793185929