1, ln(xy)=ln(x)+ln(y) (logarithmic multiplication formula) This formula means that the natural logarithm of the product of two numbers is equal to the natural logarithm of these two numbers and then added.
2.ln(x/y)=ln(x)-ln(y) (logarithmic division formula) This formula means that the natural logarithm of the quotient of two numbers is equal to the natural logarithm of these two numbers and then subtracted.
3.ln (x a) = a * ln (x) (logarithmic power formula) This formula indicates that the natural logarithm of the power of a number is equal to the product of this natural logarithm and the power of this number.
4.ln(e)= 1 (the natural logarithm of the base e of natural logarithm is equal to 1) The base e of natural logarithm is a special number called Euler number, and its natural logarithm is equal to 1.
5.e ln (x) = x (the relationship between logarithm and exponent) This formula indicates that the natural exponent of a number is equal to the power of the natural logarithm of this number based on e.
6.ln( 1+x)≈x (Taylor formula) When x is close enough to 0, the value of ln( 1+x) can be approximately calculated by Taylor formula, that is, ln( 1+x) is approximately equal to X.