(Population Growth) A bacterial population is growing continuously at a rate equal to 10 \% of its population each day. Its initial size is 10,000 organisms. How many bacteria are present after 10 days? After 30 days?
(Population Growth) A bacterial population is growing continuously at a rate equal to 10 \% of its population each day. Its initial size is 10,000 organisms. How many bacteria are present after 10 days? After 30 days?
Since the percentage growth of the population is 10 \%=0.1, we have
\frac{d P / d t}{P}=0.1, \quad \text { or } \quad \frac{d P}{d t}=0.1 P.
Here \alpha=0.1, and all solutions have the form
P(t)=c e^{0.1 t}where t is measured in days. Since P(0)=10,000, we have
c e^{(0.1)(0)}=c=10,000, \quad \text { and } \quad P(t)=10,000 e^{0.1 t}After 10 days P(10)=10,000 e^{(0.1)(10)}=10,000 e \approx 27,183, and after 30 days P(30)= 10,000 e^{0.1(30)}=10,000 e^{3} \approx 200,855 bacteria.