Can tubes be minimal surfaces?

[Applejacks]

Homework Statement

Prove that there are no tubes that are minimal surfaces

Homework Equations

F(u, v) = γ(u) + R(cosuN(v) + sinuB(v))

The Attempt at a Solution

A tube is defined to be the surface formed by drawing circles with constant radius in the normal plane in a space curve.

I know that a minimal surface is a surface with a mean curvature of zero. So to prove the tubes aren't minimal surfaces, I need to show that the mean curvature is non-zero. I just don't know what the first step to take here is. Any tips/suggestions?

 

[HallsofIvy]

Assume the curve is given by the parametric equation x= f(t), y= g(t), z= h(t). Can you write parametric equations for a point on the tube?

 

[Applejacks]

Edited the first post for a relevant equation.

Wouldn't x=rcost, y=rsint and z=t?