# Math Help - nonhomogeneous neumann boundary conditions partial perp??

1. ## nonhomogeneous neumann boundary conditions partial perp??

I am not sure what $\partial_\perp$ is? Is this a typo?

2. Originally Posted by davismj

I am not sure what $\partial_\perp$ is? Is this a typo?
Since this is a question about Neumann boundary conditions, I think you can assume that $\partial_\perp u(1,\theta)$ means the directional derivative in the direction of the normal (so the perp symbol stands for "perpendicular to the tangent")