vernecia21: you invest in $7,000 in some stock that will earn 14% annual interest compounded quarterly. how long will it take for the value of the stock to quadruple?
S = P(1+i)
n P is present value
S is future value = 4P
i = 0.14/4 = 0.035
n= unknown
4P = P*(1+0.035)
n 4 = 1.035
n log4 = log1.035
n log4 = n log1.035
log4 / log1.035 = n (quarters)
years = (log4 / log1.035) / 4
(log(4)/log(1.035))/4=
+118723 
