EE nodal analysis circuit question?

Question

I guess you can't post pictures up so I'll give you a link:

http://i250.photobucket.com/albums/gg266/funwiththeguns/Snap.png

As the title says, it is a circuit that requires the use of nodal analysis. You don't need to solve it out for me, but help me with the starting equations and I can probably take it from there. This is what I did:

v1 node: (v1/10) + (v1/5) + ((v2-v1)/2) = 6

v2 node: ((v2-v1)/2) + (v2/4) = 6 + 3

but my friend told me he had his v1 node like this:

v1 node: (v1/10) + (v1/5) = 6

Thanks in advance.

Answer 1

Your friend is wrong, you have it right.  You need to account for all branches in nodal analysis.