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Conversion formula between exponential function and logarithmic function
The general form of logarithmic function is y=logax, which is actually the inverse function of exponential function (the image of two functions is symmetric about a straight line, y = x = a y inverse function), which can be expressed as x = a y.

Therefore, there is a provision for A in the exponential function-A >; 0 and a≠ 1, different function diagrams will be formed for different sizes of a: about the axis symmetry of x, when a >; At 1, the larger a is, the closer the image is to the X axis, when 0

When a is greater than 0 and a is not equal to 1, the x power of a =N is equivalent to log (a) n = X.

Log (a k) (m n) = (n/k) log (a) (m) (n belongs to r)

Bottom-changing formula (very important)

log(a)(N)= log(b)(N)/log(b)(a)= lnN/lna = lgN/LGA

The natural logarithm of ln is based on e, which is an infinite acyclic decimal (usually only e=2.7 1828).

The common logarithm of Lg is based on 10.

Extended data:

When a> is in 1, the negative value of exponential function to x is very flat, and the positive value to x rises rapidly. When x equals 0, y equals 1. When 0

When a approaches infinity from 0 (not equal to 0), the curves of the functions tend to approach the monotonic decreasing functions of the positive and negative semi-axes of Y and X, respectively, and the monotonic increasing functions of the positive and negative semi-axes of Y and X, respectively. The horizontal straight line y= 1 is the transition position from decreasing to increasing.