Converting 2nd order ODE to Bessel Function

Click For Summary
The discussion revolves around converting a second-order ordinary differential equation (ODE) into a form suitable for Bessel functions. The original ODE, xd²y/dx² - 3dy/dx + xy = 0, is manipulated by factoring out x^-1, leading to a Bessel equation. Participants clarify that multiplying both sides by x is a valid operation, while cautioning against dividing by x if it affects the highest derivative's coefficient. The conversation also highlights the importance of considering boundary conditions when simplifying the equation. Ultimately, assistance is sought for progressing from the form x²y'' + 2xy' + x²y = 0.
rjg6
Messages
2
Reaction score
0

Homework Statement


I am attempting to solve the 2nd order ODE as follows using the generalized solution to the Bessel's equation


Homework Equations


original ODE:
xd^{2}y/dx^{2}-3dy/dx+xy=0

The Attempt at a Solution


My first thought is to bring out an x^-1 outside of the function so that I end up with:
x^{-1}(x^{2}d^{2}y/dx^{2}-3xdy/dx+x^{2}y)=0
I would then solve the resulting Bessel equation found inside the parentheses, and multiply the resulting solution by x^-1. Is this at all a legal operation? Thank you.
 
Physics news on Phys.org
There is no need for the x-1 outside. Just multiply both sides of the original equation by x.
 
Now if the opposite were true and I was trying to drop the power of x's by 1:

example: (x^3)d^{2}y/dx^{2}+(x^2)dy/dx+(x^3)y=0

Could I then instead divide by x to come up with:
(x^2)d^{2}y/dx^{2}+(x)dy/dx+(x^2)y=0

with the understanding that the solution to the resulting Bessel function would exclude any results for when x-> 0?
 
Well, because x2 still multiplying the second derivative that would be a problem any way, but you are right if you divided by something that completely got rid of a function multiplying the highest derivative, then you would have to add that condition.
 
Hey I need some help in converting the second order differential equation into..
I was able to convert the original equation into the following form x^2*y''+2x*y'+x^2*y=0
I am not able to move forward from here..
Please could you suggest some method
 
Question: A clock's minute hand has length 4 and its hour hand has length 3. What is the distance between the tips at the moment when it is increasing most rapidly?(Putnam Exam Question) Answer: Making assumption that both the hands moves at constant angular velocities, the answer is ## \sqrt{7} .## But don't you think this assumption is somewhat doubtful and wrong?

Similar threads

Replies
8
Views
2K
  • · Replies 9 ·
Replies
9
Views
1K
  • · Replies 4 ·
Replies
4
Views
3K
Replies
4
Views
1K
Replies
3
Views
2K
  • · Replies 14 ·
Replies
14
Views
1K
  • · Replies 2 ·
Replies
2
Views
2K
Replies
2
Views
2K
  • · Replies 5 ·
Replies
5
Views
3K
  • · Replies 3 ·
Replies
3
Views
1K