$$ln(a·b)= ln(a)+ln(b)$$

$$ln \left({a \over b}\right)= ln(a)- ln(b)$$

$$ln \left(a^r \right)= r·ln(a)$$

$$ln(e) = 1$$

$$y=e^x \iff x = ln(y)$$

e = 2,718 281 828 459 045 235 360 287...

$$log(a·b)= log(a)+log(b)$$

$$log \left({a \over b}\right)= log(a)- log(b)$$

$$log \left(a^r \right)= r·log(a)$$

$$log(10) = 1$$

$$y=10^x \iff x = log(y)$$