What is the Growth Rate Constant for Population Growth?

In summary, the conversation discusses finding the value of k in a given equation and using it to calculate p(0) and the growth rate after a certain time period. The method involves dividing the two equations and using logarithms. The final result is that k = 0.38376418 and the growth rate is 38.376%.
  • #1
Slimsta
190
0

Homework Statement


http://img14.imageshack.us/img14/1286/99892583.jpg

Homework Equations


in the picture

The Attempt at a Solution


so i know that
p(0)e^2k = 950
p(0)e^8k = 9500

how do i find k?
for p(0) i get 440.950939 is that right?

btw. ignore the answers in the picture
 
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  • #2
how do you find p(0) without knowing k?

try dividing you 2 equations together, then use logs
 
  • #3
lanedance said:
how do you find p(0) without knowing k?

try dividing you 2 equations together, then use logs

what i did is made both equations equal to k
so
k1 = [ln(950/p(0))] / 2
k2 = [ln(9500/p(0))] / 8

k1 = k2
[ln(950/p(0))] / 2 = [ln(9500/p(0))] / 8
solving for p(0) i get 440.9509 which let's me plug it in the main equation and get the k value..
but looks like its wrong eh?
 
  • #4
so dividing the 2 equations gives
[tex] e^{6k} = 10 [/tex]

can you solve for k?

you should get some constant a such that
[tex]k = \frac{1}{a} ln(10) [/tex]

the equation then becomes
[tex]p(t) = p(0).e^{kt} = p(0).e^{(t/a) ln(10)} = p(0).e^{ln(10^{t/a}} = p(0) .10^{t/a}[/tex]
[tex]p(0) = p(2).10^{-2/a}[/tex]

which gives me the same p(0) value as you, so your way was fine
 
  • #5
lanedance said:
so dividing the 2 equations gives
[tex] e^{6k} = 10 [/tex]

can you solve for k?

you should get some constant a such that
[tex]k = \frac{1}{a} ln(10) [/tex]

the equation then becomes
[tex]p(t) = p(0).e^{kt} = p(0).e^{(t/a) ln(10)} = p(0).e^{ln(10^{t/a}} = p(0) .10^{t/a}[/tex]
[tex]p(0) = p(2).10^{-2/a}[/tex]

which gives me the same p(0) value as you, so your way was fine

oh so i just did it the long way... kk that makes sense.
now how do i find the growth rate after 5 hours?
k = 0.38376418 so growth rate = 38.376%
 
  • #6
i would take the growth rate to mean p'(t)
 
  • #7
lanedance said:
i would take the growth rate to mean p'(t)

oh i got it! tnx man
 
Last edited:

Related to What is the Growth Rate Constant for Population Growth?

What is population growth?

Population growth refers to the change in the number of individuals in a particular population over a certain period of time. It can be positive, meaning the population is increasing, or negative, meaning the population is decreasing.

What causes population growth?

There are several factors that contribute to population growth, including increased birth rates, decreased death rates, and immigration. Changes in these factors can lead to fluctuations in population growth over time.

Why is population growth a concern?

Population growth can be a concern for several reasons. It can put pressure on resources and infrastructure, leading to issues such as food and water shortages, housing problems, and environmental degradation. It can also impact economic and social systems, potentially leading to inequality and conflicts.

How is population growth measured?

Population growth is typically measured using the natural increase rate, which is calculated by subtracting the death rate from the birth rate. It can also be measured using the total fertility rate, which is the average number of children born to a woman in her lifetime, or the net migration rate, which is the difference between immigration and emigration.

What is the current population growth rate?

The current global population growth rate is estimated to be around 1.1% per year. However, this varies greatly between countries and regions. Some countries have high population growth rates due to high birth rates, while others have negative growth rates due to low birth rates and aging populations.

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