bonjour
formules : ln(ab) = ln(a) + ln(b)
ln(1/b) = - ln(b)
ln(a/b) = ln(a) - ln(b)
ln(aⁿ) = n ln(a)
1) ln20 = ln (4 x 5) = ln 4 + ln 5
= ln 2² + ln 5
= 2ln 2 + ln 5
2) ln 100 = ln 10² = 2 ln 10 = 2 ln(2 x 5)
= 2( ln 2 + ln 5)
= 2ln 2 + 2ln 5
3) ln(4/25) = ln 4 - ln 25 = ln 2² - ln 5² = 2ln 2 - 2ln 5
4) ln√10 = ln√(2 x 5) = ln√2 + ln√5 = ln 2½ + ln 5½
= (1/2) ln2 + (1/2) ln 5
