1, logarithmic identity: alogan = n.

2.ln is the natural logarithm ln a=loge a, and the logarithm based on E is usually used for ln, and E is also a transcendental number. E is widely used in science and technology, and the logarithm with the base of 10 is generally not used.

3、ln(M/N)= lnM-lnN； ln(MN)=lnM+lnN .

4、loge(x)=ln(x)。

5.ln is a special case of logarithmic function, with 10 as the cardinal number and the domain of y=lnx as x > 0.