Electromagnetic fields

1. Jan 6, 2014

Fumbles22

Hello,

I'm stuck on this question, and it's really annoying me. I scanned the page so it has a bit more context.

It's question 3.7: "A long wire carrying a steady current is placed in a uniform magnetic field parallel to it's own length. What is the shape of the magnetic field lines close to the wire?".

I approached the problem like this:

I'm close to the answer in the back of the book (which i'll withhold for now) but it still isn't right. Unfortunately, I can't see what i've done wrong.

I was hoping that someone could point out any gaps in my working.

2. Jan 6, 2014

rude man

I don't see what's wrong with what you did. Maybe you could express r as sqrt(x^2 +y^2) but other than that ...

3. Jan 6, 2014