Parametric Equation of Surface

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The discussion focuses on finding parametric equations for a cylinder defined by the equation x² + y² = 5, extending between the planes z = 0 and z = 1. Participants clarify that the cylinder's radius is 5, and they explore translating the circle's equation into polar coordinates to derive the parametric equations for x and y. The variable v is identified as the parameter for the z-coordinate, which ranges from 0 to 1. Ultimately, the connection between the circular cross-section and the cylindrical shape is established, leading to a solution for the parametric equations. The conversation emphasizes understanding the geometric properties of the cylinder to formulate the correct equations.
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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
 

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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.
 
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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?
 
Question: A clock's minute hand has length 4 and its hour hand has length 3. What is the distance between the tips at the moment when it is increasing most rapidly?(Putnam Exam Question) Answer: Making assumption that both the hands moves at constant angular velocities, the answer is ## \sqrt{7} .## But don't you think this assumption is somewhat doubtful and wrong?

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