Verhulst equation - integration problem

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In summary, the problem involves integrating the unforced Verhulst equation from t_{0}-\epsilon to t_{0}+\epsilon and taking the limit as \epsilon approaches 0. This leads to a requirement for the discontinuity in g, which must be shown to be true for the given function. The equation is commonly used in biology to model population dynamics. The exercise also involves the application of Green's functions to a nonlinear problem.
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billiards
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Verhulst equation -- integration problem

Homework Statement



Integrate the unforced Verhulst equation over [itex]t[/itex] from [itex]t_{0}-\epsilon[/itex] to [itex]t_{0}+\epsilon[/itex], take the limit [itex]\epsilon \downarrow 0[/itex] and show this lead to the following requirement for the discontinuity in g:

[tex]\stackrel{lim}{\epsilon \downarrow 0}[g(t,t_{0})]^{t_{0}+\epsilon}_{t_{0}-\epsilon}=F_{0}[/tex]

Homework Equations



Unforced Verhulst equation:
[tex]\dot{g}-g+g^{2}=F_{0} \delta(t-t_{0})[/tex]

Where:
[tex]g(t)=\frac{1}{Ae^{-t}+1}[/tex]

The Attempt at a Solution



It looks to me that in order to solve this problem I need to show that:
[tex]\int^{t_{0}+\epsilon}_{t_{0}-\epsilon}g dt=\int^{t_{0}+\epsilon}_{t_{0}-\epsilon}g^{2} dt[/tex]

This will not be true of any function g in general, so we must show that it is true for the function in this problem. i.e. Show that:

[tex]\int^{t_{0}+\epsilon}_{t_{0}-\epsilon}\frac{1}{Ae^{-t}+1} dt=\int^{t_{0}+\epsilon}_{t_{0}-\epsilon}\frac{1}{(Ae^{-t}+1)^{2}} dt[/tex]

Is this along the right lines? This is where I get stuck as I'm not very well practiced in integration. I think I can do the one on the left, but am struggling with the one on the right.

Thanks for any help.
 
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Any helpers out there?

Incidentally (for those interested -- and in case you didn't already know) this equation is used in biology to model population dynamics. http://en.wikipedia.org/wiki/Logistic_function

I'm doind an exercise on the application of Green's functions to nonlinear problem.
 

1. What is the Verhulst equation and what is its significance?

The Verhulst equation is a mathematical model that describes population growth over time. It takes into account both the growth rate and carrying capacity of a population, making it a more realistic and accurate representation of population growth compared to other models. This equation is commonly used in ecology, biology, economics, and other fields to study and predict population dynamics.

2. How is the Verhulst equation integrated?

The Verhulst equation is integrated using the technique of separation of variables. This involves separating the variables (population and time) on opposite sides of the equation and then integrating both sides. The resulting equation can then be solved for the population at a specific time.

3. What is the significance of the Verhulst constant in the equation?

The Verhulst constant, also known as the carrying capacity, represents the maximum population size that an environment can sustain. It is a crucial parameter in the Verhulst equation as it determines the point at which population growth reaches its maximum and begins to level off.

4. How does the Verhulst equation account for environmental factors?

The Verhulst equation takes into account environmental factors through the carrying capacity constant and the growth rate constant. The carrying capacity represents the maximum population size that an environment can sustain, while the growth rate represents the rate at which the population increases or decreases. These factors can be adjusted to reflect changes in the environment, such as availability of resources or presence of predators.

5. What are some limitations of the Verhulst equation?

The Verhulst equation is a simplified model and does not account for all factors that can affect population growth, such as random events and interactions between different species. It also assumes a constant carrying capacity, which may not be realistic in some populations. Additionally, the equation may not accurately predict long-term population dynamics as it is based on a single population with no immigration or emigration. Therefore, it is important to use the Verhulst equation in conjunction with other models and data for a more comprehensive understanding of population dynamics.

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