Critical Points and Graphs of Differential Equations

In summary, the equation dy/dt = alpha - y^2 has been discussed in terms of finding the critical points and their stability for different values of alpha. For alpha < 0, there is one critical point at y = sqrt(alpha) and it is asymptotically stable. For alpha = 0, there are two critical points at y = 0 and y = infinity, both of which are unstable. For alpha > 0, there are two critical points at y = sqrt(alpha) and y = -sqrt(alpha), both of which are unstable. The solution for alpha > 0 is given by y = sqrt(alpha) - e^(-alpha*t). Finally, a bifurcation diagram can be plotted to show
  • #1
nallapanther
1
0
Consider the equation dy/dt = alpha - y^2

a) Find all of the critical points. How does it change as alpha < 0, alpha = 0 or alpha > 0?

b) In each case of different alphas, consider the graph of f(y) vs y and determine whether each critical point is asympototically stable, semistable, or unstable.

c) For alpha > 0, find the solution.

d) Plot a bifurcation diagram - this is a plot of the location of the critical points as a function of alpha (plot a graph alpha as x-axis and y-axis showing the location of the critical point)
 
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  • #2
To get the best out of these forums, you should show us your attempt at the problem so we can target assistance to the place you most need it.

For example - do you know how the critical points of y are related to dy/dx ?
 
  • #3
hey mate post up what you've done and i'll show you the next steps

the diff plots can be daunting in the beginning but if you keep practicing them they become very easy to interpret

let us know
 

FAQ: Critical Points and Graphs of Differential Equations

What is a critical point in a differential equation?

A critical point in a differential equation refers to a point where the derivative of the equation is equal to zero. This means that the slope of the graph at that point is horizontal, and can indicate a possible maximum, minimum, or point of inflection on the graph.

How do you find the critical points of a differential equation?

To find the critical points of a differential equation, you must set the derivative of the equation equal to zero and solve for the variable. This will give you the x-value of the critical point. Then, you can use this value to find the corresponding y-value by plugging it into the original equation.

What information can critical points provide about a differential equation?

Critical points can provide information about the behavior of the graph of a differential equation. They can indicate the location of maximum and minimum points, as well as points of inflection. They can also help in determining the overall shape and trajectory of the graph.

Can a differential equation have more than one critical point?

Yes, a differential equation can have multiple critical points. These points can be either real or complex, depending on the nature of the equation. In some cases, there may be an infinite number of critical points, as in the case of a polynomial with an infinite number of solutions.

How can the graph of a differential equation be used to determine critical points?

The graph of a differential equation can visually show the location of critical points by indicating where the slope of the graph is equal to zero. By looking at the shape and behavior of the graph, one can also predict the type of critical point (maximum, minimum, or point of inflection) that exists at a particular point on the graph.

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