Mahalanobis - am 2004-10-22 00:33 - Rubrik: EconoSchool
dc meinte am 22. Oct, 02:07:
See also rule of 72
http://invest-faq.com/articles/analy-rule-72.htmlAt 10%, your money doubles in about ~7.2 years.
Mahalanobis antwortete am 22. Oct, 03:33:
Well,
I guess I am more attached to the number 69. In the continuous case you end up witht*g = ln(2),
and in the discrete case with
t*ln(1+g) = ln(2).
But then I would argue that a McLaurin expansion of ln(1+g) is approximately g for small g.
ln(1+g) = g - (1/2)g^2 + (1/3)g^3 - (1/4)g^4 + ...
so t is approximately ln(2)/g again.
