Finding the distance between a point and a level curve

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SUMMARY

The discussion focuses on finding the point on the level curve defined by the equation \( \frac{5}{8} x^2 - \frac{3}{4} xy + \frac{5}{8} y^2 = 1 \) that is closest to the point (1, -1). The solution involves calculating the gradient vector \( \left( \frac{5}{4}x - \frac{3}{4}y, \frac{5}{4}y - \frac{3}{4}x \right) \) and applying the method of Lagrange multipliers to optimize the distance function while adhering to the constraint of the curve. The realization that the problem is about optimizing a function with a constraint is crucial for arriving at the correct solution.

PREREQUISITES
  • Understanding of gradient vectors and their significance in optimization.
  • Familiarity with the method of Lagrange multipliers for constrained optimization.
  • Knowledge of level curves and their mathematical representation.
  • Basic proficiency in calculus, particularly in solving equations with two variables.
NEXT STEPS
  • Study the method of Lagrange multipliers in detail to apply it effectively in optimization problems.
  • Learn how to derive and interpret gradient vectors in multivariable calculus.
  • Explore the concept of level curves and their applications in optimization scenarios.
  • Practice solving distance optimization problems involving constraints to solidify understanding.
USEFUL FOR

Students studying calculus, mathematicians interested in optimization techniques, and anyone looking to enhance their problem-solving skills in constrained optimization scenarios.

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Homework Statement



Find the point on the curve defined by 5/8 x^2 - 3/4 xy + 5/8 y^2 = 1

That is closest to the point (1,-1)


Homework Equations





The Attempt at a Solution



I started by finding the gradient vector. < (5/4x - 3/4 y) , (5/4y - 3/4x) >

I could not figure out if that was even the right direction to go in because I don't know how I'd even find a distance formula
 
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You have one equation with two unknowns, so you need another equation relating those two variables. You do have information to construct another equation: the distance from the curve to the specified point is a minimum. Write down an equation that expresses that condition, and then solve the two equations for the two unknowns.
 
ah nvm i realized its just optimizing a function with another contraining function.. i think... so i could use lagrange multipliers

thanks for your help
 

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