/*! 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 18 Evaluate each iterated integral.... [FREE SOLUTION] | 91Ó°ÊÓ

91Ó°ÊÓ

Evaluate each iterated integral. \(\int_{-2}^{2} \int_{0}^{2} x e^{-y} d x d y\)

Short Answer

Expert verified
The value of the integral is \(2e^{2} - 2e^{-2}\).

Step by step solution

01

Identify the Inner Integral

The given double integral is \(\int_{-2}^{2} \int_{0}^{2} x e^{-y} \, dx \, dy\). The inner integral is \(\int_{0}^{2} x e^{-y} \, dx\). Identify this as our focus for the first step.
02

Evaluate the Inner Integral

The inner integral is \(\int_{0}^{2} x e^{-y} \, dx\). Since \(e^{-y}\) is treated as a constant with respect to \(x\), the integral becomes \(e^{-y} \int_{0}^{2} x \, dx\). Compute the integral of \(x\), which is \(\frac{x^2}{2}\), evaluated from 0 to 2.
03

Compute the Inner Integral

Evaluate \(\frac{x^2}{2}\) from 0 to 2: \(\left.\frac{x^2}{2}\right|_0^2 = \frac{2^2}{2} - \frac{0^2}{2} = 2\). Substitute back: \(e^{-y} \times 2 = 2e^{-y}\). The result of the inner integral is \(2e^{-y}\).
04

Setup the Outer Integral

Now substitute the result of the inner integral into the outer integral: \(\int_{-2}^{2} 2e^{-y} \, dy\).
05

Evaluate the Outer Integral

The outer integral is \(\int_{-2}^{2} 2e^{-y} \, dy\). Solve it by factoring out the 2: \(2\int_{-2}^{2} e^{-y} \, dy\). The integral of \(e^{-y}\) is \(-e^{-y}\).
06

Compute the Outer Integral

Evaluate \(-e^{-y}\) from -2 to 2: \(2[-e^{-y}]_{-2}^2 = 2\left(-e^{-2} - (-e^{2})\right) = 2(e^{2} - e^{-2})\).
07

Simplify the Result

Multiply the result by 2: \(2(e^{2} - e^{-2}) = 2e^{2} - 2e^{-2}\). This is the final value of the integral.

Unlock Step-by-Step Solutions & Ace Your Exams!

  • Full Textbook Solutions

    Get detailed explanations and key concepts

  • Unlimited Al creation

    Al flashcards, explanations, exams and more...

  • Ads-free access

    To over 500 millions flashcards

  • Money-back guarantee

    We refund you if you fail your exam.

Over 30 million students worldwide already upgrade their learning with 91Ó°ÊÓ!

Key Concepts

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

Calculus
Calculus is a branch of mathematics that provides techniques to handle change and motion. It is divided into two main parts, differential calculus, which deals with rates of change and slopes of curves, and integral calculus, which focuses on accumulation of quantities, such as areas under or between curves. In this exercise, we're dealing with integral calculus as we are evaluating an integral to compute the accumulated value of a particular function within a given boundary.
To understand the importance of integral calculus, think of calculating areas. For example, finding the area under curves or shapes is practically done using integrals.
  • This process is called integration, which helps in solving real-world problems involving distances, areas under curves, and more.
  • In contexts like physics, it can be used for calculations involving velocity, acceleration, and other dynamic quantities.
Thus, calculus is fundamental not just in mathematics but also in fields like physics, engineering, and economics.
Double Integral
A double integral is a specific type of integral for functions of two variables, offering a way to compute volume under a surface. The iterated integral you see in this exercise is essentially a double integral.
The iterated integral \\(\int_{-2}^{2} \int_{0}^{2} x e^{-y} \, dx \, dy\) ot only involves integration over more than one dimension, but here the integration is done iteratively:
  • Inner Integral: First, integrate with respect to \(x\), treating \(y\) as a constant.
  • Outer Integral: Then, use the result to integrate with respect to \(y\).
Instead of just finding the area under a single curve, double integrals consider the volume under a surface over a specific region. This two-step process, integrating first one variable and then another, allows for precise calculations over two-dimensional regions. They can be visually imagined as stacking layers of area calculations over one another.
Integration Techniques
Mastering various integration techniques allows us to solve complex integrals efficiently. Given this exercise, let's explore some of the key strategies we employed.
First, dealing with constants simplifies integration. Here, \(e^{-y}\) was considered constant when integrating with respect to \(x\). This approach helped in reducing the complexity of the integral.
After simplifying, recognizing standard integral forms is useful to quickly solve integrals. For example, knowing the integral of \(x\) is \(\frac{x^2}{2}\) and of \(e^{-y}\) is \(-e^{-y}\) speeds up the solution process.
  • Factoring out constants, such as \(2\) in the outer integral, is another useful technique. It separates the constant from the main core of the integration, making calculations less cumbersome.
  • Finally, always remember to evaluate definite integrals over specified bounds to capture the total effect across the given interval.
By applying these techniques, one can effectively manage and solve complex integrals with ease, broadening their ability to tackle a range of mathematical problems.

One App. One Place for Learning.

All the tools & learning materials you need for study success - in one app.

Get started for free

Most popular questions from this chapter

An automobile manufacturer sells cars in America, Europe, and Asia, charging a different price in each of the three markets. The price function for cars sold in America is \(p=20-0.2 x\) (for \(0 \leq x \leq 100\) ), the price function for cars sold in Europe is \(q=16-0.1 y \quad(\) for \(0 \leq y \leq 160),\) and the price function for cars sold in Asia is \(r=12-0.1 z\) (for \(0 \leq z \leq 120\) ), all in thousands of dollars, where \(x, y,\) and \(z\) are the numbers of cars sold in America, Europe, and Asia, respectively. The company's cost function is \(C=22+4(x+y+z)\) thousand dollars. a. Find the company's profit function \(P(x, y, z)\). [Hint: The profit will be revenue from America plus revenue from Europe plus revenue from Asia minus costs, where each revenue is price times quantity. b. Find how many cars should be sold in each market to maximize profit. [Hint: Set the three partials \(P_{x}, P_{y}\), and \(P_{z}\) equal to zero and solve. Assuming that the maximum exists, it must occur at this point.]

Use Lagrange multipliers to minimize each function \(f(x, y)\) subject to the constraint. (The minimum values do exist.) $$ f(x, y)=x y, \quad y=x+8 $$

For a double integral there are two possible orders of integration. How many possible orders of integration are there for a triple integral?

If a function has a critical point at which \(f_{x x}>0\) what can you conclude?

The following table shows how a driver's blood-alcohol level (\% grams per dekaliter) affects the probability of being in a collision. A collision factor of 3 means that the probability of a collision is 3 times as large as normal. Fit an exponential curve to the data. Then use your curve to estimate the collision factor for a blood-alcohol level of \(15 .\) $$ \begin{array}{cc} \hline \text { Blood-Alcohol } & \\ \text { Level } & \text { Collision Factor } \\ 0 & 1 \\ 6 & 1.1 \\ 8 & 3 \\ 10 & 6 \end{array} $$

See all solutions

Recommended explanations on Math Textbooks

View all explanations

What do you think about this solution?

We value your feedback to improve our textbook solutions.

Study anywhere. Anytime. Across all devices.