Find a parametric representation for the surface.
The part of the plane
z = x + 1
that lies inside the cylinder
x^2 + y^2 = 1.
(Enter your answer as a comma-separated list of equations. Let x, y, and z be in terms of s and/or θ.)

the answer is:
x=scos(θ), y=ssin(θ), z=scos(θ)+1

Question: This all makes sense to me except for the variable s. What is it, anyhow? It looks like s is equivalent to r in this case, which is 1, so why are the parameterizations not x=rcosθ or simply x=cosθ?

Question

Find a parametric representation for the surface.
The part of the plane 
z = x + 1
 that lies inside the cylinder 
x^2 + y^2 = 1.
 (Enter your answer as a comma-separated list of equations. Let x, y, and z be in terms of s and/or θ.)

the answer is:
x=scos(θ), y=ssin(θ), z=scos(θ)+1

Question: This all makes sense to me except for the variable s. What is it, anyhow? It looks like s is equivalent to r in this case, which is 1, so why are the parameterizations not x=rcosθ or simply x=cosθ?

anonymous · Answer

i think s is just a direct replacement of r in this case, just different notation for some reason. i've never seen it in that form and i'm just finishing up calc III later today. i wouldn't put too much thought into it. i'm sure if i'm wrong someone else will come up with some information for you.

anonymous · Answer

Yeah, that's what I figured. I just thought I'd put the question out there to see what others thought. Thanks a lot for your reply.