It is proved that loga(N)=x, then a x = n, and both sides take the logarithm with B as the base, logb (a x) = logb (n), xlogb(a)=logb(N), and x=logb(N)/logb(a), so Loga (n
The formula of changing base is a common logarithmic operation formula in high school mathematics, which can be used together with other logarithmic operation formulas. In the calculation, the calculation difficulty is often reduced, and the logarithmic operation in the middle and high schools can be solved faster.
Log bottom function:
If ax = N(a>；; 0, and a≠ 1), then the number x is called the logarithm of the base of n, denoted as x=logaN, and read as the logarithm of the base of n, where a is called the base of logarithm and n is called a real number.
In general, the function y = logax(a >；; 0, and a≠ 1) is called logarithmic function, that is, a function with power (real number) as independent variable, exponent as dependent variable and base constant as constant is called logarithmic function.
Where x is the independent variable and the domain of the function is (0, +∞), that is, x >；; 0。 It is actually the inverse function of exponential function, which can be expressed as x=ay. Therefore, the stipulation of a in exponential function is also applicable to logarithmic function.