Does this ODE have an equilibrium?

In summary, the conversation discusses the existence of an equilibrium in a system of connected reservoirs governed by a given ODE. The possibility of an extraneous solution is also mentioned. The conversation concludes with a request for insight on the conditions for equilibrium in the system.
  • #1
explorer58
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Homework Statement


Two reservoirs are connected. Water drains from one reservoir to the other, governed by the following ODE:

dh/dt= -k1*(h)^0.5 -k2*(h-H)^0.5 , H<0, k1,k2>0

Does an equilibrium exist? What happens in terms of Picard's Existence Theorem? Draw a phase diagram of possible h* values.
Find an upper and lower bound for time it takes for reservoir to completely empty using respectively the maximum and minimum rates of decay of h on a well selected interval for h.

Homework Equations


The Attempt at a Solution



My friend and I are at odds. He says you can find a solution by saying

-k1*(h)^0.5 -k2*(h-H)^0.5=0
=> k1*h^0.5 = -k2*(h-H)^0.5

and then squaring both sides and solving for h. I on the other hand think that that will introduce an extraneous solution. It appears to me that, as it stands, the way it is set up, all terms are positive, and as such there is no equilibrium for this equation. However that's also just as confusing, because that would mean the rest of the question was a trick.

Any insight would be wholly appreciated.
 
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  • #2
dh/dt stands for the rate of change of water in the system. If there is equilibrium, what condition must dh/dt satisfy?
 

1. What is an equilibrium in an ODE?

An equilibrium in an ODE is a point where the derivative of the function is equal to zero. This means that the function is not changing at that point, and it is considered a steady state.

2. How do I determine if an ODE has an equilibrium?

You can determine if an ODE has an equilibrium by setting the derivative of the function equal to zero and solving for the variable. If a solution exists, then the ODE has an equilibrium.

3. Can an ODE have more than one equilibrium?

Yes, an ODE can have more than one equilibrium. This can occur when there are multiple solutions to the equation when the derivative is set to zero.

4. What does it mean if an ODE has no equilibrium?

If an ODE has no equilibrium, it means that the function is constantly changing and has no steady state. This could indicate a chaotic behavior or a system that is constantly evolving.

5. How does the existence of an equilibrium affect the behavior of an ODE?

The existence of an equilibrium can greatly affect the behavior of an ODE. If the equilibrium is stable, it means that the function will approach that point and remain there. If the equilibrium is unstable, it means that the function will move away from that point. The type of equilibrium can also affect the stability of the system.

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