MHB How was u_1 and u_2 star determined

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The discussion centers on the determination of steady states for the system defined by the equations for u_1 and u_2. The steady states identified are (0,0), (1,0), and (0,1), but these do not always represent the general steady states of the system. The book provides specific formulas for the steady states, u_1^* and u_2^*, without explanation, which are derived from setting the derivatives to zero. The correct steady states can be found by solving the simultaneous equations u_1 + a_{12}u_2 = 1 and u_2 + a_{21}u_1 = 1. Understanding these relationships is crucial for analyzing the dynamics of the system.
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$$\begin{array}{lcl}
\frac{du_1}{d\tau} & = & (1-u_1-a_{12}u_2)\\
\frac{du_2}{d\tau} & = & (1-u_2-a_{21}u_1)
\end{array}
$$

The steady states for this system are $(0,0)$, $(1,0)$, and $(0,1)$.

But then the book says without explanation

$\displaystyle u_1^* = \frac{1-a_{12}}{1-a_{12}a_{21}}$

and

$\displaystyle u_2^* = \frac{1-a_{21}}{1-a_{12}a_{21}}$

Never mind solve the problem
 
Last edited:
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dwsmith said:
$$\begin{array}{lcl}
\frac{du_1}{d\tau} & = & (1-u_1-a_{12}u_2)\\
\frac{du_2}{d\tau} & = & (1-u_2-a_{21}u_1)
\end{array}
$$

The steady states for this system are $(0,0)$, $(1,0)$, and $(0,1)$.

But then the book says without explanation

$\displaystyle u_1^* = \frac{1-a_{12}}{1-a_{12}a_{21}}$

and

$\displaystyle u_2^* = \frac{1-a_{21}}{1-a_{12}a_{21}}$

Never mind solve the problem

The are the solutions to the pair of equations for a steady state:

$$\begin{array}{lcl}
\frac{du_1}{d\tau} & = & 0\\
\frac{du_2}{d\tau} & = & 0
\end{array}
$$

Which is the system of simultaneous equations:

$$\begin{array}{lcl}
u_1+a_{12}u_2 & = & 1\\
u_2+a_{21}u_1 & = & 1
\end{array}
$$

Also, $(0,0)$, $(1,0)$, and $(0,1)$ are not in general the steady states of the system.

CB
 
Last edited:

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