Solving Minimization Problem w/ Lagrange Multipliers

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In summary, to solve the given problem using Lagrange multipliers, we set up the objective function J(x,y) and the constraint function C(x,y) and then use the method of Lagrange multipliers to find the critical points. However, in this particular problem, the values of \lambda obtained may not be valid as they assume that neither x nor y are zero. It is also possible that there may be more than one solution. A visual representation of the problem may help in understanding the solution better.
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Homework Statement



Solve the following problems using Lagrange multipliers
(a) Minimise J (x; y) = x^2 + y^2 subject to C (x; y) = 4x^2 + 3y^2 = 12:

Homework Equations


The Attempt at a Solution



i got h(x,y)=x^2+y^2+[tex]\lambda[/tex](4x^2+3y^2-12)

dh/dx=2x+8x[tex]\lambda[/tex]=0
dh/dy=2y+6y[tex]\lambda[/tex]=0

then i got [tex]\lambda[/tex]=-1/4=-1/3?impossible to slove it
 
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The values you obtained for [tex]\lambda[/tex] made an assumption that neither x or y are zero. Can you really make that claim? Also, maybe there is more than one solution (i.e. a min and a max)? Might help to draw a picture.
 
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FAQ: Solving Minimization Problem w/ Lagrange Multipliers

What is a minimization problem in mathematics?

A minimization problem in mathematics involves finding the lowest possible value of a mathematical function or expression, often subject to certain constraints. It is the opposite of a maximization problem, which seeks to find the highest possible value.

What are Lagrange multipliers?

Lagrange multipliers are a method for solving constrained optimization problems, such as minimization problems. They involve using a system of equations to find the minimum or maximum value of a function subject to one or more constraints.

Why do we use Lagrange multipliers in minimization problems?

Lagrange multipliers are used in minimization problems because they allow us to take into account any constraints that may affect the minimum value of a function. This method helps us find the exact solution, rather than an approximate one.

What are the steps involved in solving a minimization problem using Lagrange multipliers?

The steps involved in solving a minimization problem using Lagrange multipliers are:1. Formulate the objective function and any constraints.2. Set up the Lagrangian function by multiplying each constraint by a Lagrange multiplier.3. Take the partial derivatives of the Lagrangian function with respect to each variable.4. Set the partial derivatives equal to zero and solve the resulting system of equations.5. Substitute the values obtained in step 4 into the Lagrangian function to find the minimum value of the objective function.

Are there any limitations to using Lagrange multipliers in minimization problems?

One limitation of using Lagrange multipliers is that they can only be applied to problems with equality constraints. In addition, the method may not always yield a unique solution, and it can be computationally expensive for complex problems.

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