Answer:
ln A - ln P
r = ----------------
t
Step-by-step explanation:
The exponential growth function is A = Pe^(rt), where r is the annual growth rate as a decimal fraction and t is the number of years.
Taking the natural log of both sides, we get
ln A = ln P + rt, or
ln A - ln P = rt
Since t = 5 yr,
ln A - ln P
r = ----------------
t
and in this case,
ln A - ln P 11.989-9.21034
r = ---------------- = ------------------------ = 0.56
t 5
The annual growth rate, to the nearest percent, is 56%
