MHB How was u_1 and u_2 star determined

  • Thread starter Thread starter Dustinsfl
  • Start date Start date
  • Tags Tags
    Star
Dustinsfl
Messages
2,217
Reaction score
5
$$\begin{array}{lcl}
\frac{du_1}{d\tau} & = & (1-u_1-a_{12}u_2)\\
\frac{du_2}{d\tau} & = & (1-u_2-a_{21}u_1)
\end{array}
$$

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:
Physics news on Phys.org
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:
I have the equation ##F^x=m\frac {d}{dt}(\gamma v^x)##, where ##\gamma## is the Lorentz factor, and ##x## is a superscript, not an exponent. In my textbook the solution is given as ##\frac {F^x}{m}t=\frac {v^x}{\sqrt {1-v^{x^2}/c^2}}##. What bothers me is, when I separate the variables I get ##\frac {F^x}{m}dt=d(\gamma v^x)##. Can I simply consider ##d(\gamma v^x)## the variable of integration without any further considerations? Can I simply make the substitution ##\gamma v^x = u## and then...

Similar threads

  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 4 ·
Replies
4
Views
2K
  • · Replies 1 ·
Replies
1
Views
3K
Replies
5
Views
2K
  • · Replies 1 ·
Replies
1
Views
2K
Replies
3
Views
2K
Replies
2
Views
3K
  • · Replies 11 ·
Replies
11
Views
2K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 1 ·
Replies
1
Views
10K