Parametric Equation of Surface

  • Thread starter Thread starter Phil Frehz
  • Start date Start date
  • Tags Tags
    Parametric Surface
Click For Summary

Homework Help Overview

The discussion revolves around finding parametric equations for a portion of a cylinder defined by the equation x² + y² = 5, which extends between the planes z = 0 and z = 1. Participants are exploring the translation of this geometric shape into parametric form using parameters u and v.

Discussion Character

  • Exploratory, Conceptual clarification, Mathematical reasoning

Approaches and Questions Raised

  • Participants express uncertainty about how to translate the cylinder's equation into parametric equations. There is discussion about using polar coordinates to represent x and y, while z is noted to vary simply within a limited interval. Some participants also question the interpretation of the cylinder's radius and its implications for the equations.

Discussion Status

The discussion is ongoing, with participants sharing their thoughts on how to approach the problem. Some guidance has been provided regarding the use of polar coordinates, and there is acknowledgment of the relationship between the circle's equation and the cylinder's structure. However, there is no explicit consensus on the final parametric equations yet.

Contextual Notes

Participants are working under the constraints of homework guidelines, which may limit the amount of direct assistance they can receive. There is also a focus on understanding the geometric implications of the equations involved.

Phil Frehz
Messages
13
Reaction score
0

Homework Statement


Find parametric equations for the portion of the cylinder x2 + y2 = 5 that extends between the planes z = 0 and z=1.

Homework Equations


I can't really find any connection but I do have
x=a*sinv*cosu
y=a*sinv*sinu
z=a*cosv

The Attempt at a Solution



I understand that there is a cylinder of radius 5 between z=0 and z=1 however I don't understand how to translate it in terms of u & v. In polar coordinates I know r extends from the origin (r=0) to the cylindrical curve (r=1), while theta is from 0 to 2pi.

Attached is the solution, not sure how to connect the information together
 

Attachments

  • Screen Shot 2015-07-19 at 4.53.46 PM.png
    Screen Shot 2015-07-19 at 4.53.46 PM.png
    2.4 KB · Views: 561
Physics news on Phys.org
Phil Frehz said:

Homework Statement


Find parametric equations for the portion of the cylinder x2 + y2 = 5 that extends between the planes z = 0 and z=1.

Homework Equations


I can't really find any connection but I do have
x=a*sinv*cosu
y=a*sinv*sinu
z=a*cosv

The Attempt at a Solution



I understand that there is a cylinder of radius 5 between z=0 and z=1 however I don't understand how to translate it in terms of u & v. In polar coordinates I know r extends from the origin (r=0) to the cylindrical curve (r=1), while theta is from 0 to 2pi.

Attached is the solution, not sure how to connect the information together
Just focusing on the circle in the x-y plane for the moment, think about how you would translate the circle's equation into polar coordinates. That should give you equations for x and y in terms of a parameter. The inequality for z is very simple, with v = z, but within a limited interval.
 
  • Like
Likes   Reactions: Phil Frehz
Mark44 said:
Just focusing on the circle in the x-y plane for the moment, think about how you would translate the circle's equation into polar coordinates. That should give you equations for x and y in terms of a parameter. The inequality for z is very simple, with v = z, but within a limited interval.

Thanks for the input, I looked into it and found that v was the varying parameter, converting x and y to polar coordinates gave me the answer. Thanks again
 
Phil Frehz said:

Homework Statement


Find parametric equations for the portion of the cylinder x2 + y2 = 5 that extends between the planes z = 0 and z=1.

Homework Equations


I can't really find any connection but I do have
x=a*sinv*cosu
y=a*sinv*sinu
z=a*cosv

The Attempt at a Solution



I understand that there is a cylinder of radius 5 between z=0 and z=1 however I don't understand how to translate it in terms of u & v. In polar coordinates I know r extends from the origin (r=0) to the cylindrical curve (r=1), while theta is from 0 to 2pi.

Attached is the solution, not sure how to connect the information together

Is x2 + y2 = 5 the equation of a cylinder of radius = 5?

https://en.wikipedia.org/wiki/Circle
 
SteamKing said:
Is x2 + y2 = 5 the equation of a cylinder of radius = 5?

https://en.wikipedia.org/wiki/Circle

That's how the book stated the problem, I understood it as the cylinder created when the circle x2 + y2 = 5 is extended between z=0 and z=1
 
Phil Frehz said:
That's how the book stated the problem, I understood it as the cylinder created when the circle x2 + y2 = 5 is extended between z=0 and z=1
Since the sections thru the cylinder along the z-axis are circles, then the equation of the circle,
namely x2 + y2 = r2, must be satisfied.

If the radius of the circular sections of the cylinder is indeed r = 5, then what must the equation of the cylinder be?
 

Similar threads

  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 5 ·
Replies
5
Views
2K
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 10 ·
Replies
10
Views
3K
  • · Replies 4 ·
Replies
4
Views
2K
Replies
1
Views
1K
  • · Replies 7 ·
Replies
7
Views
4K
  • · Replies 4 ·
Replies
4
Views
3K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 3 ·
Replies
3
Views
3K