In​ 2012, the population of a city was 6.27 million. The exponential growth rate was 1.47​% per year.
​a) Find the exponential growth function.
​b) Estimate the population of the city in 2018.
​c) When will the population of the city be 8 ​million?
​d) Find the doubling time.

Respuesta :

Answer:

a) [tex]a(t)= 6.27e^{0.0147*t}[/tex]

b) 6.84 million

c) 2028.52

d) 47 years

Step-by-step explanation:

a)Here we know standard exponential growth rate is

[tex]a(t)= ae^{k*t}[/tex]

In this put t=0 and a(t)=6.27 million

thus we get a = 6.27 million

now [tex]\frac{da}{dt}=a(t)k[/tex]

  this is equal to(in 2012)=[tex]\frac{1.47}{100}*=0.0147[/tex]

b)Put t = 6

we get

[tex]a(t)= 6.27e^{0.0147*6}[/tex]

=6.84 million

c) [tex]8 = 6.27e^{0.0147*t}[/tex]

  take log both sides

we get 16.52 years

d) [tex]2*6.27=6.27e^{0.0147*t}[/tex]

take log both sides we get 47 years to get double the current population.