Rule of 72
(1+k%)x=2
x=log1+k%2=ln2ln(1+k%)
using L'Hospital's Rule:
limx→cf(x)g(x)=limx→cf′(x)g′(x)
so, limx→0xln1+x=limx→0111+x=limx→01+x=1
so, ln2ln(1+k%)≈ln2k%=100×ln2k≈69.3k
(1+k%)x=2
x=log1+k%2=ln2ln(1+k%)
using L'Hospital's Rule:
limx→cf(x)g(x)=limx→cf′(x)g′(x)
so, limx→0xln1+x=limx→0111+x=limx→01+x=1
so, ln2ln(1+k%)≈ln2k%=100×ln2k≈69.3k