# Thread: Solve this ordinary differential equation if you can

1. ## Solve this ordinary differential equation if you can

Hi everyone!

Can you please help me solve this ordinary differential equation in the attachment below?

Thank you.

2. ## Re: Solve this ordinary differential equation if you can

This is a separable ODE.

$\dfrac{y^2-b^2}{y^2+b^2}dy = -\dfrac{x^2+a^2}{x^2-a^2}dx$

$y-b\arctan\left(\dfrac{y}{b}\right) = -x-2\int\left(\dfrac{a^2}{x^2-a^2}\right)dx = -x-2a\text{tanh}^{-1}\left(\dfrac{x}{a}\right)+C$

The final integral can be split up using Partial Fractions if you do not like inverse hyperbolic functions.

3. ## Re: Solve this ordinary differential equation if you can

I have some of these problems that i am finding hard to solve. can you please provide me the solutions of them?

Thank you.

4. ## Re: Solve this ordinary differential equation if you can

Edit: Dang! I just noticed how old this thread was. Never mind.

We aren't here to do your homework for you. But I do have some suggestions for you:
1. Don't post sideways images.
2. Don't post images anyway. Type them. That way we can edit your work with suggestions or corrections.
3. Post each problem in a separate thread, showing what you have tried. Do you seriously think anyone is going to post solutions to 30 problems for you?

5. ## Re: Solve this ordinary differential equation if you can

Originally Posted by SlipEternal
This is a separable ODE.

$\dfrac{y^2-b^2}{y^2+b^2}dy = -\dfrac{x^2+a^2}{x^2-a^2}dx$

$y-b\arctan\left(\dfrac{y}{b}\right) = -x-2\int\left(\dfrac{a^2}{x^2-a^2}\right)dx = -x-2a\text{tanh}^{-1}\left(\dfrac{x}{a}\right)+C$

The final integral can be split up using Partial Fractions if you do not like inverse hyperbolic functions.
Hello,
I got the answer from my integral calculator $-2b\arctan{(\frac{y}{b})}+y+C$=$-a\ln{(|a-x|)}+a\ln{(|a+x|)}-x+C$

What is the difference between your answer and my answer?