Population Relative Growth Rate Concept?

I got confused by the concept of relative growth rate and growth rate. I understand that when it says "relative growth rate of the population is 3%", it means dP/dt = 0.03P.

However, when it says "growth rate of the population is 3%", does it mean:

dP/dt = 0.03P

or

dP/dt = 0.03?

To me the phrase "growth rate" seems more like a rate than a constant. Can someone help me out please?

Thanks in advance!

Re: Population Relative Growth Rate Concept?

Hey LLLLLL.

It means 0.03P since a 3% increase is 100% + 3% but since its is a derivative we look at the change which is 0.03P.

Re: Population Relative Growth Rate Concept?

Quote:

Originally Posted by

**chiro** Hey LLLLLL.

It means 0.03P since a 3% increase is 100% + 3% but since its is a derivative we look at the change which is 0.03P.

Hi Chiro,

Thank you so much for your reply!

I get that the rate is going to contain 0.03. But I'm still a bit confused about why the rate depends on P.

I'm not sure whether the phrase "growth rate of the population is 3%" means that the rate is constantly 0.03 or is 3% of the current population.

Thank you again for your help!

Re: Population Relative Growth Rate Concept?

It is something like

$\displaystyle \frac{dP}{dt}=aP$

where $\displaystyle a$ does not depend on $\displaystyle t$ nor $\displaystyle P$. This kind of models are called Malthusian Malthusian growth model - Wikipedia, the free encyclopedia

Re: Population Relative Growth Rate Concept?

Quote:

Originally Posted by

**LLLLLL** I got confused by the concept of relative growth rate and growth rate. I understand that when it says "relative growth rate of the population is 3%", it means dP/dt = 0.03P.

However, when it says "growth rate of the population is 3%", does it mean:

dP/dt = 0.03P

or

dP/dt = 0.03?

To me the phrase "growth rate" seems more like a rate than a constant. Can someone help me out please?

Thanks in advance!

It has to be dP/dt = 0.03P, since it's 3%, and you never do a percent unless it's the relative growth rate.

- Hollywood

Re: Population Relative Growth Rate Concept?

Quote:

Originally Posted by

**Ruun**

Thank you for that link!