Integrating Population Differential Equation: Need Help!

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SUMMARY

The discussion focuses on integrating the population differential equation dP/dt = k1(P) - k2(P), where k1 and k2 are proportionality constants. The correct solution is P(t) = A e^{(k1-k2)t}, where A is a constant defined as A = e^{C(k1-k2)}. The integration process involves recognizing the relationship between the constants and ensuring that k1 - k2 is correctly placed in the exponent. The user expresses uncertainty about their integration method, but the provided solution clarifies the correct approach.

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andrewdavid
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I have this population differential equation dP/dt=k1(P)-k2(P) where k1 and k2 are proportionality constants. I need to integrate and analyze where k1>k2, k1=k2, and k1<k2. Trouble is, I don't think I'm integrating this right. I get P=e^(t+C)(k1-k2). I know this should be easy but I don't think it's right. Little help?
 
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the solution is

[tex]P(t) = Ae^{(k_1-k_2)t}[/tex]

for some constant [itex]A[/itex], which might be equivalent to yours, or it might not (I can't tell whether you mean that [itex]k_1-k_2[/itex] is in the exponent or not. If it is, then yours is fine).
 
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Yes,the jonction between the 2 formulae is made simply

[tex]P(t)=e^{\left[\left(k_{1}-k_{2}\right)(t+C)\right]}=e^{C\left(k_{1}-k_{2}\right)}e^{\left(k_{1}-k_{2}\right) t} =A e^{\left(k_{1}-k_{2}\right) t}[/tex]

,where i defined

[tex]A=:e^{C\left(k_{1}-k_{2}\right)}[/tex]

Daniel.
 

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