Solving Navier-Stokes for Vo: why don't I get the professor's answer?

[cycling4life]

I need to solve 0=u[(d/dr)((1/r)*(d/dr)(r*Vo))] for Vo
the prof gets Vo=Co*r/2+C1/r

I don't get the same answer as him, does anyone know how to do this?

 

[zhermes]

If you plug in his answer does it work?
What about your answer?