Surface area of parametric equation

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SUMMARY

The discussion focuses on finding the surface area of a parametric surface defined by the equations r(s,t) = under the constraint s² + t² ≤ 1. The tangent plane at the point (2,3,1) is correctly identified as -2x + 3y - z = 4. To compute the surface area, the user intends to apply the surface area formula |rs x rt| integrated over the specified limits. A suggestion is made to convert the double integral to polar coordinates for easier computation.

PREREQUISITES
  • Understanding of parametric equations in three-dimensional space
  • Knowledge of vector calculus, specifically cross products
  • Familiarity with surface area calculations for parametric surfaces
  • Basic proficiency in polar coordinate transformations
NEXT STEPS
  • Study the derivation and application of the surface area formula |rs x rt| for parametric surfaces
  • Learn how to convert double integrals into polar coordinates effectively
  • Explore examples of tangent planes for parametric surfaces
  • Practice solving surface area problems under various constraints
USEFUL FOR

Students and educators in calculus, particularly those focusing on multivariable calculus and vector calculus, as well as anyone involved in mathematical modeling of surfaces.

Pete_01
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Homework Statement


For the surface with parametric equations r(st)=<st, s+t, s-t>, find the equation of the tangent plane at (2,3,1).
Find the surface area under the restriction s^2 + t^2 <=(lessthanorequalto) 1


Homework Equations





The Attempt at a Solution


I already figured out the equation of the tangent plane: -2x+3y-z=4, but I am not sure how to find the surface area? I want to use the SA equation |rs x rt| integrated from ds 0 to 1 and dt 0 to 2pi but i am not having much luck. Any ideas?
 
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Pete_01 said:

Homework Statement


For the surface with parametric equations r(st)=<st, s+t, s-t>, find the equation of the tangent plane at (2,3,1).
Find the surface area under the restriction s^2 + t^2 <=(lessthanorequalto) 1


Homework Equations





The Attempt at a Solution


I already figured out the equation of the tangent plane: -2x+3y-z=4, but I am not sure how to find the surface area? I want to use the SA equation |rs x rt| integrated from ds 0 to 1 and dt 0 to 2pi but i am not having much luck. Any ideas?

If you are integrating with dA=ds dt, from ds 0 to 1, then dt would be 0 to \sqrt{1-s^2}. Try converting the double integral to polar coordinates with dA=r dr d_theta.
 
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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