Lagrange Multipliers Find 3 positive numbers?

In summary, Lagrange multipliers are a method for finding the maximum or minimum value of a function subject to constraints. They introduce a new variable, known as the Lagrange multiplier, to the original function and its constraints, creating a system of equations that can be solved to find the critical points and determine the optimal value of the function. This method is commonly used in various fields such as economics, physics, and engineering to optimize a given situation. The steps to solve a problem using Lagrange multipliers include identifying the function and constraints, setting up the equations, solving for the critical points, and substituting them into the original function.
  • #1
tak13
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Homework Statement



Find 3 positive numbers x, y and z for which: their sum is 24 and which maximizes the product: P = x2y3z. Find the maximum product.



The Attempt at a Solution



Ok, I know how to set up the equations.

x + y + z = 24

Delta(F) <2xy3z, 2x2y2z, x2y3>

fx = 2xy3z = λ
fy = 2x2y2z = λ
fz = x2y3> = λ

Substitution part is where I am stuck. Any helps would be awesome! Thanks!
 
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  • #2
Nevermind, after a major number crunching, I got it. thanks!
 

1. What are Lagrange multipliers?

Lagrange multipliers are a method for finding the maximum or minimum value of a function subject to constraints. It involves using a system of equations to find critical points of the function and determining which one is the maximum or minimum.

2. How do Lagrange multipliers work?

Lagrange multipliers work by introducing a new variable, known as the Lagrange multiplier, to the original function and its constraints. This creates a system of equations that can be solved to find the critical points of the function and determine the maximum or minimum value.

3. What is the purpose of using Lagrange multipliers?

The main purpose of using Lagrange multipliers is to optimize a function subject to constraints. It allows for the determination of the maximum or minimum value of the function, while also satisfying the given constraints.

4. What are the steps to solve a problem using Lagrange multipliers?

The first step is to identify the function and its constraints. Then, set up the Lagrange multiplier equations by combining the function and constraints and finding the partial derivatives. Next, solve the system of equations to find the critical points. Finally, substitute the critical points into the original function to determine the maximum or minimum value.

5. What are some real-life applications of Lagrange multipliers?

Lagrange multipliers have many real-life applications in fields such as economics, physics, and engineering. Some common examples include finding the maximum profit for a company given certain constraints, optimizing the shape of a bridge to minimize material usage, and determining the trajectory of a projectile subject to air resistance.

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