Les logarithmes

\( ln(ab) = ln(a) + ln(b) \) ;

\( ln(1/b) = - ln(b) \) ;

\(ln(a/b) = ln(a) - ln(b) \) ;

\( ln(a^n) = n ln(a) \) ;

\( ln(x) = y \Leftrightarrow x = e^y \)

\( log(ab) = log(a) + log(b) \) ;

\( log(1/b) = - log(b) \) ;

\( log(a/b) = log(a) - log(b) \) ;

\( log(a^n) = n log(a) \) ;

\( log(x) = y \Leftrightarrow x = 10^y \)