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Simple multivariable problem w/ ellipse

  • Thread starter MeMoses
  • Start date
  • #1
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Homework Statement



If u=x^3 + 3xy + y^3, determine du/dx on the ellipse 2x^2+3y^2=1

2. The attempt at a solution

Imagine I just use partial derivative somehow, but I'm not sure what the question is asking by on the ellipse. I have a feeling its just something simple that I'm overlooking. Any help is appreciated. Thanks

Homework Statement





Homework Equations





The Attempt at a Solution

 

Answers and Replies

  • #2
HallsofIvy
Science Advisor
Homework Helper
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The chain rule:
[tex]\frac{du}{dx}= \frac{\partial u}{\partial x}+ \frac{\partial u}{\partial y}\frac{dy}{dx}[/tex]
You get dy/dx from the requirement that [itex]2x^2+ 3y^2= 1[/itex], of course.
 

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