Find rate of population growth

D

dubb

New member
Joined
Oct 3, 2014
Messages
28
These ones always confuse me. Here it is:
the function P(t) = 4.23e^.042t, gives the population of a city in millions, where t is years since 1990, find the rate of population growth in 2012.

Do I basically just plug in 22 for t? I got 10.656 but is that the rate?

Thanks for your help.
 
dubb said:
These ones always confuse me. Here it is:
the function P(t) = 4.23e^.042t, gives the population of a city in millions, where t is years since 1990, find the rate of population growth in 2012.

Do I basically just plug in 22 for t? I got 10.656 but is that the rate?

Thanks for your help.
Click to expand...

Rate generally equates with derivative and that is the case here.
 
would the derivative of P(t) = 4.23e^.042t be .17766e^.042t?
 
Ok, I got .45, so the rate of population growth is .45? Is that how it is written? or would it be like a percentage?
 
dubb said:
Ok, I got .45, so the rate of population growth is .45? Is that how it is written? or would it be like a percentage?
Click to expand...

If you know what it means and the answer is just for you, the 0.45 is enough but it depends on what your instructor or whoever wants. For anyone other than yourself, you should probably put units with it and since the population P was given in millions of people and the time was in years, the answer would be something like "the rate of population growth in 2012 was 0.45 million people per year" or maybe just "0.45 million people per year"

Edit: Oh, and BTW, I would probably round to 3 places since that is what you were given for the problem.
 
Last edited:
You must log in or register to reply here.
Top