Parametric Paraboloid In Polar Coordinates

In summary, the conversation is about finding a parametric form for the paraboloid z=x2+y2 from z=0 to z=1. The proposed solution is to use polar coordinates as parameters u and v, with the parametric equations \vec{r}(u,v)=(vcosu,vsinu,v^{2}) and u:[0..2\pi],v:[0..1]. There is some confusion about the terminology, with the suggestion to use cylindrical coordinates instead. Overall, the proposed solution is deemed acceptable.
  • #1
Lancelot59
646
1
I just want to see if my logic is sound here. If we have the paraboloid z=x2+y2 from z=0 to z=1, and I wanted a parametric form of that I think this should work for polar coordinates:

[tex]\vec{r}(u,v)=(vcosu,vsinu,v^{2})[/tex]
[tex]u:[0..2\pi],v:[0..1][/tex]

Does this make sense?
 
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  • #2
not really i think you are still defining cartesian coords, though its not exactly clear what you are trying to do
 
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  • #3
Thise are perfectly good parametric equations for the paraboloid, using "polar coordinates" in the xy-plane as parameters (actually you are using v= r, [itex]u= \theta[/itex]).
 
  • #4
ok, so parameterise in terms of 2D polar coords, that makes more sense
 
  • #5
Then it isn't in 3D anymore...I meant to say cylindrical coordinates, so that's my bad with the terminology.
 

FAQ: Parametric Paraboloid In Polar Coordinates

1. What is a parametric paraboloid in polar coordinates?

A parametric paraboloid in polar coordinates is a geometric shape that can be described using polar coordinates, which are coordinates that use a distance from the origin and an angle from the positive x-axis. The shape is created by rotating a parabola around its axis.

2. How is a parametric paraboloid different from a regular paraboloid?

A parametric paraboloid is defined using a set of equations in polar coordinates, while a regular paraboloid is defined using a set of equations in Cartesian coordinates. Additionally, a parametric paraboloid is created by rotating a parabola around its axis, while a regular paraboloid is created by graphing a quadratic equation in three-dimensional space.

3. What are some real-life applications of parametric paraboloids?

Parametric paraboloids are commonly used in architecture and engineering for the design of structures such as roofs, domes, and arches. They are also used in the design of optical reflectors and satellite dishes.

4. What are the key features of a parametric paraboloid?

The key features of a parametric paraboloid are its vertex, focus, and directrix. The vertex is the point at which the paraboloid's axis intersects the plane, the focus is the point at which all of the paraboloid's lines of symmetry meet, and the directrix is the line that the paraboloid's lines of symmetry are perpendicular to.

5. How can parametric paraboloids be graphed and visualized?

Parametric paraboloids can be graphed and visualized using mathematical software or by hand. By plugging in different values for the parameters in the equations, different points on the surface of the paraboloid can be plotted and connected to create a 3D representation. Additionally, 3D graphing calculators can also be used to easily visualize and manipulate parametric paraboloids.

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