# Homework Help: Solution Of A Differential Equation]

1. May 8, 2008

### NEWO

Hi all I was wondering if i could get some help with this.

1. I need to be able to solve a second order differential equation,

2. d^2(y)/dx^2= c/x

where c is an arbitary constant.

I was thinking that the solution would take form of a trigonometrial eqauation, would this be correct?

N

3. The attempt at a solution

2. May 8, 2008

### D H

Staff Emeritus
You left this part of the template blank. What work have you done on the problem?

3. May 8, 2008

### MathematicalPhysicist

Well it's quite easy, here's a hint: succesive 'something' will do the trick.

4. May 8, 2008

### HallsofIvy

WHY would you tnink "that the solution would take form of a trigonometrial eqauation"?

5. May 8, 2008

### tiny-tim

Hi NEWO!

Noo … you're thinking of d²y/dx² = -cy.

Hint: just say the equation in ordinary English:

"y is a function of x, and if you differentiate it twice, you get c/x."

6. May 8, 2008

### HallsofIvy

If you let $v= dy/dx$ then $d^2y/dx^2= dv/dx$ so your equation becomes $dv/dx= c/x$. What is v(x)?

7. May 9, 2008

### MathematicalPhysicist

Halls, isn't your hint really the solution?

8. May 9, 2008

### HallsofIvy

Well, almost. There is still a tiny amount of work to be done. And I suspect that "NEWO" won't bother to come back to look at the responses.