# Solve dy/dx + xy/4-x^2 =1

• May 18th 2010, 07:12 PM
skydiver1921
Solve dy/dx + xy/4-x^2 =1
How can this problems be worked out?

dy/dx + xy/4-x^2 =1 solve this equation for y when x=0 , y=1 and the abs val of x is less than 2.

I know some calculus, but I need help with this. Thank you.
• May 18th 2010, 09:17 PM
silencecloak
Quote:

Originally Posted by skydiver1921
How can this problems be worked out?

dy/dx + xy/4-x^2 =1 solve this equation for y when x=0 , y=1 and the abs val of x is less than 2.

I know some calculus, but I need help with this. Thank you.

Wouldn't your initial values cancel out almost the entire problem?

$y' + \frac{(0)(1)}{4} - (0)^2 = 1$

$y' = 1$
• May 19th 2010, 06:26 AM
skydiver1921
No, because I need to solve for Y not Y-prime. I think there is a method to get Y on its own and then plug in the variables.
• May 19th 2010, 06:32 AM
mr fantastic
Quote:

Originally Posted by skydiver1921
How can this problems be worked out?

dy/dx + xy/4-x^2 =1 solve this equation for y when x=0 , y=1 and the abs val of x is less than 2.

I know some calculus, but I need help with this. Thank you.

Start by using the integrating facor technique to get the general solution. Please show your work and say where you're stuck if you need more help.
• May 19th 2010, 06:36 AM
skydiver1921
Is this a first order differential equation? I'm asking because I do not know how to perform the technique Mr. Fantastic suggested.
• May 19th 2010, 06:41 AM
mr fantastic
Quote:

Originally Posted by skydiver1921
Is this a first order differential equation? I'm asking because I do not know how to perform the technique Mr. Fantastic suggested.

Yes it is. But I don't understand why you're trying to solve it if you haven't been taught the technique ...? Have you reviewed your class notes and textbook (just in case you have been taught and have just forgotten)
• May 19th 2010, 08:15 AM
skydiver1921
No, unfortunately our original teacher died before we could learn the material and our new substitute cannot speak english very well so it is very difficult to follow his teaching. He has assinged the problem and has not taught it. I need the solved version of this for him. Thank you very much for your help mr fantastic.
• May 19th 2010, 08:39 PM
mr fantastic
Quote:

Originally Posted by skydiver1921
No, unfortunately our original teacher died before we could learn the material and our new substitute cannot speak english very well so it is very difficult to follow his teaching. He has assinged the problem and has not taught it. I need the solved version of this for him. Thank you very much for your help mr fantastic.

Read this: Integrating Factor -- from Wolfram MathWorld

Watch this: YouTube - Diff Eq #3 Integrating Factor Example

Now attempt the question. Show all your working and say where you get stuck.