Finding Wronskian of Diff. Eq. with Abel's Formula: Help Needed

In summary, the conversation discusses using Abel's Formula to find the Wronskian of two solutions of a given differential equation without solving the equation. The formula is W(y1, y2)(x) = ce-∫p(x)dx, where p(x) is derived from the differential equation. The conversation also touches on the importance of using correct parentheses and simplifying the integrated result. The value for c is determined by evaluating the Wronskian at some initial x value.
  • #1
physics=world
110
0
1. Use Abel's Formula to find the Wronskian of two solutions of the given differential equation
without solving the equation.


x2y" - x(x+2)y' + (t + 2)y = 0

2.

Abel's Formula

W(y1, y2)(x) = ce-∫p(x)dx3.

I put it in the form of

y" + p(x)y' + q(x)y = 0

to find my p(x) to use for Abel's formulap(x) = - (x+2 / x)this would give:

W(y1, y2)(x) = ce-∫(-)(x+2 / x)dxI'm not sure if I'm going in the right direction. I need some help.
 
Last edited by a moderator:
Physics news on Phys.org
  • #2
physics=world said:
1. Use Abel's Formula to find the Wronskian of two solutions of the given differential equation
without solving the equation.


x2y" - x(x+2)y' + (t + 2)y = 0

2.

Abel's Formula

W(y1, y2)(x) = ce-∫p(x)dx





3.

I put it in the form of

y" + p(x)y' + q(x)y = 0

to find my p(x) to use for Abel's formula


p(x) = - (x+2 / x)
Your use of parentheses is commendable, although you have them in the wrong place here and below.
You should have p(x) = -(x + 2)/x

What you wrote is the same as ##-(x + \frac 2 x)##.
physics=world said:
this would give:

W(y1, y2)(x) = ce-∫(-)(x+2 / x)dx


I'm not sure if I'm going in the right direction. I need some help.
This seems OK to me (aside from the parentheses thing). Are you having trouble with the integration?
 
  • #3
After integrating I get:

ce(x) + 2ln(x)

Is this the answer? What about the value for c?
 
  • #4
physics=world said:
After integrating I get:

ce(x) + 2ln(x)
You should simplify that.
physics=world said:
Is this the answer? What about the value for c?
I believe that c is W(y1(x), y2(x))(x0). IOW, the Wronskian of the two functions, evaluated at some initial x value.
 

Related to Finding Wronskian of Diff. Eq. with Abel's Formula: Help Needed

1. What is the Wronskian of a differential equation?

The Wronskian is a mathematical tool used to determine if a set of functions is linearly independent. For a differential equation, it is used to determine if a set of solutions is linearly independent and therefore forms a fundamental set of solutions.

2. How do you find the Wronskian using Abel's formula?

Abel's formula is a method for finding the Wronskian of a set of functions. It involves taking the determinant of a matrix containing the functions and their derivatives. The formula is:
W(x) = e∫p(x)dx * det(f(x))

3. What is the significance of finding the Wronskian of a differential equation?

Finding the Wronskian allows us to determine if a set of solutions to a differential equation is linearly independent. This is important because a fundamental set of solutions is necessary to find a general solution to a differential equation.

4. What are the limitations of using Abel's formula to find the Wronskian?

Abel's formula is only applicable for linear differential equations with constant coefficients. It cannot be used for other types of differential equations, such as non-linear or variable coefficient equations.

5. Are there any other methods for finding the Wronskian of a differential equation?

Yes, there are other methods for finding the Wronskian, such as using the properties of determinants or using the Cauchy-Euler equation. However, Abel's formula is often the most efficient and straightforward method for finding the Wronskian.

Similar threads

  • Calculus and Beyond Homework Help
Replies
2
Views
475
  • Calculus and Beyond Homework Help
Replies
1
Views
568
  • Calculus and Beyond Homework Help
Replies
1
Views
2K
  • Calculus and Beyond Homework Help
Replies
1
Views
2K
  • Calculus and Beyond Homework Help
Replies
1
Views
2K
  • Calculus and Beyond Homework Help
Replies
7
Views
1K
  • Calculus and Beyond Homework Help
Replies
18
Views
2K
  • Calculus and Beyond Homework Help
Replies
10
Views
1K
  • Calculus and Beyond Homework Help
Replies
1
Views
3K
  • Calculus and Beyond Homework Help
Replies
1
Views
639
Back
Top