For the surface S (helicoid or spiral ramp) swept out by the line segment joining the point (2t, cost, sint) to (2t,0,0) where 0 is less than or equal to t less than or equal to pi. (a) Find a parametrisation for this surface S and of the boundary A of this surface. I can only guess that x=rcost y=rsint z=t 0 less than or equal to t less than or equal to pi 0 less than or equal to r less than or equal to 1 Is this right or totally bogus? (b) For the vector field F=(x,y,z) compute the flux of F through the surface S. Assume the normal to the surface has a non-negative k component at t=0. No idea because what is the surface S? It has no equation. (c) Compute integral (F*dr) where A is the boundary curve of the surface S and F is the force field (x,y,z). I think I just use Stokes Theorem for (c), but I'm having trouble setting it up since again I have no equation for the surface S. I also don't know how the whole line segment joining works into it. I can evaluate the integrals, I just have trouble setting them up. If anyone could help me with these three I would appreciate it. Just explain what's going on.