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Demystifying the Natural Logarithm (ln)After understanding the exponential function our next target is the natural logarithm. Given how the natural log is described in math books, there's little "natural" about it: it's defined as the inverse of e^x, a strange enough exponent already. But there's a fresh, intuitive explanation: The natural log gives you the time needed to reach a certain level of growth.

via Betterexplained