What is the surface parametrization for rotating y=Cosh(x) about the x-axis?

[chaotixmonjuish]

I'm having problems understanding surface parametrization from differential geometry.

We are given two general forms for parametrization:
$$\alpha$$(u,v) = (u,v,0)
and x(u,v)=(u,v,f(u,v))


This is one I'm especially stuck on:

y=Cosh(x) about the x-axis

$$\alpha$$(u,v)=(u, Cosh[v],0)

x(u,v) = (u, Cosh[v]cos(u), Cosh[v]sin(u))

I think that's right.

 

[arkajad]

I do not understand the notation in these "general forms". Which textbook are you using?

 

[tiny-tim]

hi chaotixmonjuish!

(have an alpha: α and a theta: θ )

y=Cosh(x) about the x-axis

$$\alpha$$(u,v)=(u, Cosh[v],0)

x(u,v) = (u, Cosh[v]cos(u), Cosh[v]sin(u))

are you talking about the surface of revolution obtained by rotating y = coshx about the x-axis?

if so, if one of your parameters (u) is equal to x, then the other sensible paramter to choose would be θ, an angle round the x-axis …

(so you'll get a nice "square-ish" (x,θ) grid on the surface)

anyway, your y will always be cosh(u), won't it, not cosh of some other parameter v ?