/*! This file is auto-generated */ .wp-block-button__link{color:#fff;background-color:#32373c;border-radius:9999px;box-shadow:none;text-decoration:none;padding:calc(.667em + 2px) calc(1.333em + 2px);font-size:1.125em}.wp-block-file__button{background:#32373c;color:#fff;text-decoration:none} Problem 86 In Exercises 85-88, find values ... [FREE SOLUTION] | 91Ó°ÊÓ

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In Exercises 85-88, find values of \( x, y \) and \( \lambda \) that satisfy the system. These systems arise in certain optimization problems in calculus, and \( \lambda \) is called a Lagrange multiplier. \( \left\\{\begin{array}{l} \hspace{1cm} 2x + \lambda = 0\\\ \hspace{1cm} 2y + \lambda = 0\\\ x + y - 4 = 0\end{array}\right. \)

Short Answer

Expert verified
The solution to the system of equations is \( x = 2 \), \( y = 2 \), \( \lambda = -4 \).

Step by step solution

01

Rearrange the first two equations

Rearrange the first two equations to solve for \( x \) and \( y \). This gives us the equations \( x = - \lambda/2 \) and \( y = - \lambda/2 \).
02

Substitute \( x \) and \( y \) into the third equation

By substituting \( x \) and \( y \) from our rearranged equations into the third equation \( x + y - 4 = 0 \), we have \(- \lambda/2 - \lambda/2 - 4 = 0 \) which simplifies to \( -\lambda - 4 = 0 \).
03

Solve for \( \lambda \)

Solve the equation \( -\lambda - 4 = 0 \) to find the value of \( \lambda \). This gives us \( \lambda = -4 \)
04

Substitute \( \lambda \) into the rearranged first two equations

Now that we have found \( \lambda \), we can substitute it back into the rearranged equations for \( x \) and \( y \). From the first equation, this gives us \( x = -(-4)/2 = 2 \) and from the second equation \( y = -(-4)/2 = 2 \).

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Key Concepts

These are the key concepts you need to understand to accurately answer the question.

Optimization Problems
Optimization problems deal with finding the best solution from a set of possible choices. In mathematics, these problems often aim to maximize or minimize a certain quantity under given constraints. In calculus, optimization problems typically involve functions subject to constraints, and tools like the method of Lagrange multipliers come in handy.

In an optimization context, you might need to find the highest profit, the lowest cost, or the largest area, for example. The key is knowing how to set up the problem. Consider what quantity you want to optimize and identify the constraints that this quantity might have.
  • A function represents the quantity to optimize, often called the objective function.
  • Constraints are conditions that the solution must satisfy, which can often be equations or inequalities.
The Lagrange multipliers method is perfect for when you have constraints that must be satisfied along with the objective function. It involves introducing an extra variable, called a Lagrange multiplier, which helps in taking into account the constraints.
System of Equations
A system of equations is a collection of two or more equations with the same set of unknowns. Solving such systems is a fundamental activity in mathematics because it allows us to find values for the variables that satisfy all equations at once.

There are various techniques for solving systems of equations:
  • Substitution Method: Solve one equation for one variable and substitute this expression into the other equations.
  • Elimination Method: Add or subtract equations to eliminate a variable.
  • Graphical Method: Graph the equations and look for their intersections.
In the given exercise, the system involves linear equations and revolves around finding the values of \( x \), \( y \), and \( \lambda \). It involves rearranging and substituting the expressions to isolate the variables and solve the system step by step. The Lagrange multiplier comes into play as a crucial method for optimization under constraints within this system.
Calculus
Calculus is a vast area of mathematics focusing primarily on limits, functions, derivatives, integrals, and infinite series. It provides the tools necessary for analyzing changes and motion in both physical and abstract systems.

Two of its main branches are:
  • Differential Calculus: Deals with the concept of a derivative which represents the rate of change of a function. It helps in finding tangents to curves and identifies maximum and minimum points.
  • Integral Calculus: Concerns itself with integration, which is the process of finding the areas under and between curves, among other applications.
In optimization problems, particularly those handled by Lagrange multipliers, calculus is used to understand the behavior of functions subjected to constraints. By taking derivatives and using them in solving equations, one can find critical points of a function that help determine optimal solutions. Derivatives are especially useful in linear optimization, where determining zero slopes can lead to identifying minimum or maximum values that satisfy system constraints.

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Most popular questions from this chapter

A company has budgeted a maximum of \( \$1,000,000 \) for national advertising of an allergy medication. Each minute of television time costs \( \$100,000 \) and each one-page newspaper ad costs \( \$20,000 \). Each television ad is expected to be viewed by 20 million viewers, and each newspaper ad is expected to be seen by 5 million readers. The company's market research department recommends that at most \( 80\% \) of the advertising budget be spent on television ads. What is the optimal amount that should be spent on each type of ad? What is the optimal total audience?

In Exercises 41-54, sketch the graph and label the vertices of the solution set of the system of inequalities. \( \left\\{\begin{array}{l} x + y \le 1\\\ -x + y \le 1\\\ \hspace{1cm} y \ge 0\end{array}\right. \)

In Exercises 21-32, use a graphing utility to graph the inequality. \( x^2 + 5y - 10 \le 0 \)

In Exercises 13-16, sketch the region determined by the constraints. Then find the minimum and maximum values of the objective function (if possible) and where they occur, subject to the indicated constraints. Objective function: \( z = 5x + \dfrac{1}{2}y \) Constraints: \( \hspace{1cm} x \ge 0 \) \( \hspace{1cm} y \ge 0 \) \( \dfrac{1}{2}x + y \le 8 \) \( x + \dfrac{1}{2}y \ge 4 \)

A warehouse supervisor is told to ship at least 50 packages of gravel that weigh 55 pounds each and at least 40 bags of stone that weigh 70 pounds each. The maximum weight capacity of the truck to be used is 7500 pounds. Find and graph a system of inequalities describing the numbers of bags of stone and gravel that can be shipped.

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