Logarithmic function is exponential function y = a x(a >；; 0 and a is not 1), expressed as y=log ax. Obviously, log ax indicates how many powers of a are equal to x, and the logarithm with the base of 10 is called ordinary logarithm and recorded as lgx；;

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In mathematics, e is one of the most commonly used transcendental numbers. Usually used as the base of natural logarithm, that is, In(x)= the logarithm of x with base e =2. 7 1828 1828459

Lnx refers to the logarithm of X based on E, so when x=e, the logarithm of E is 1, for example, log 10 = 1.