# Homework Help: Second Order Differential Equation

1. Sep 3, 2007

### danny271828

I need to solve the equation

$$\frac{d^{2}}{dx^{2}}$$$$\Psi$$ + $$\frac{2}{x}$$$$\frac{d}{dx}$$$$\Psi$$ = $$\lambda$$$$\Psi$$

Can anyone help me get a start on this problem? I've been guessing at a few solutions with no results... I'm not asking anyone to solve the problem... just a few hints on starting... maybe regarding the form of the solution... Thanks

2. Sep 3, 2007

### Kummer

Multiply throught by $$x^2$$ to get,
$$x^2 \Psi '' + 2x\Psi ' - \lambda x^2 \Psi = 0$$
Now I believe this can be converted to Bessel's equations.
The solution is in terms of Bessel functions (possibly using the Bessel function of the 3rd kind, i.e. Hankel function).

3. Sep 4, 2007

### HallsofIvy

If it is not a form of Bessel's equation, use Frobenius' method.

4. Sep 4, 2007

### chaoseverlasting

Dont know if this would work, but you could substitute p=dy/dx, and convert this into a linear DE in p. Once you get a solution for p, replace p by dy/dx and thats another linear DE to solve.

5. Sep 4, 2007

### HallsofIvy

But there is no "y" in the problem! Presumably you meant $\Psi$ but then, since $\Psi$ itself appears in the equation, that substitution won't work.

6. Sep 9, 2007

### chaoseverlasting

Yeah. Sorry.... Didnt realize that.