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.

Usually, we call the logarithm with 10 as the common logarithm, and record log 10N as lgN. In addition, the logarithm based on irrational number E = 2.7 1828 is often used in scientific counting, and the logarithm based on e is called natural logarithm, while logeN? Write it as n.

Extended data

1, basic knowledge

①

②

③ There is no logarithm between negative number and zero.

④

2, identity and proof

a^log(a)(n)=n(a & gt； 0，a≠ 1)

Understanding and derivation of logarithmic formula operation in rhyme world (8 sheets)

Deduction: Prove the identity of log (a) (a n) = n.

At a>0 and a≠ 1, n >；; 0 o'clock

Let: when log(a)(N)=t, (t∈R) is satisfied.

Then there is a t = n；;

a^(log(a)(N))=a^t=N。