Given a surface defined in parametric equations, find the surface area

In summary, the student is seeking clarification on finding the gradient and is confused about the use of the vector r_u and r_v. The scientist explains that these vectors represent partial derivatives and can provide a more accurate solution, but it is possible to find the gradient with just the current knowledge. The student is advised to review the material on partial derivatives and seek guidance from their instructor or TA for further clarification.
  • #1
theBEAST
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Homework Statement


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The Attempt at a Solution


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So I am trying to find the gradient because in class we were taught that the surface area is the magnitude of the gradient divided by the magnitude of the dot product between the gradient and normal to the projected surface.

I noticed in the textbook, the solution uses some sort of vector r_u and r_v, however this was not covered in class so I am somewhat confused.

Is it possible to do this problem with just the knowledge I know?
 
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  • #2


Dear student,

Thank you for reaching out and seeking clarification on this topic. I understand your confusion about the use of the vector r_u and r_v in finding the gradient. These vectors represent the partial derivatives of the surface with respect to the u and v parameters, respectively. They can also be thought of as the direction in which the surface is changing the most.

While it is possible to find the gradient using just the knowledge you have, understanding and using these partial derivatives can provide a more accurate and efficient solution. I would suggest reviewing the material on partial derivatives and their applications in order to better understand this concept.

Additionally, I would also recommend seeking guidance from your instructor or TA if you are still struggling with this concept. They can provide further clarification and examples to help you better understand and apply the concept of finding the gradient.

I hope this helps. Keep up the good work and don't hesitate to reach out with any further questions.



Scientist
 

Related to Given a surface defined in parametric equations, find the surface area

1. How do you find the surface area of a surface defined in parametric equations?

The surface area of a surface defined in parametric equations can be found by using the formula:

S = ∫∫ ||∂r/∂u x ∂r/∂v|| dA, where r(u,v) is the parametric equation of the surface and u and v are the parameters.

2. What is the significance of using parametric equations to define a surface?

Parametric equations allow us to describe a surface in terms of two parameters, which makes it easier to calculate its properties such as surface area and volume. It also allows us to visualize and manipulate the surface in a more intuitive way.

3. Can the surface area of a surface defined in parametric equations be negative?

No, the surface area cannot be negative as it represents the total area of the surface. If the calculated surface area is negative, it means that the orientation of the surface is incorrect and needs to be reversed.

4. Are there any specific techniques or methods for finding the surface area of a surface defined in parametric equations?

Yes, there are several techniques such as using a double integral, using vector calculus, and using parametric surfaces of revolution. The choice of method depends on the complexity of the surface and the available tools.

5. Can the surface area of a surface defined in parametric equations be infinite?

Yes, the surface area can be infinite if the surface extends infinitely in one or more directions. In such cases, we can use a limit to find an approximation of the surface area or define a finite region of the surface to calculate the area within that region.

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