/*! 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 46 Find the centroid of the region ... [FREE SOLUTION] | 91Ó°ÊÓ

91Ó°ÊÓ

Find the centroid of the region bounded by the given curves. \(y=x^{3}, \quad x+y=2, \quad y=0\)

Short Answer

Expert verified
Centroid is at (0, 0.5).

Step by step solution

01

Find the Points of Intersection

To find the points of intersection for the curves, solve for points where the curves meet. For the curves given, identify intersections between \( y = x^3 \) and \( x + y = 2 \). Substitute \( y = x^3 \) into \( x + y = 2 \), giving \( x + x^3 = 2 \). Solve for \( x \), resulting in values \( x = 1 \) and \( x = -1 \). Check these with \( y = 0 \), making possible points \((x,0)\). Thus, points are \((1,1)\), \((-1,-1)\), and intersection with x-axis, \((1,0)\) and \((-1,0)\).
02

Set Up the Integral for Area

The area of the region needs to be found by setting up an integral. The integrals needed are those with limits from \(-1\) to \(1\), as these are the bounds where the curves intersect. The region is bounded by \(y=x^3\) from below and \(y = 2 - x\) from above. The area \(A\) can be calculated by \[A = \int_{-1}^{1} ((2-x) - x^3)\, dx\].
03

Calculate the Area

Compute the integral for the area:\[A = \int_{-1}^{1} (2 - x - x^3)\, dx = \left[ 2x - \frac{x^2}{2} - \frac{x^4}{4} \right]_{-1}^{1}\].Evaluating this from \(-1\) to \(1\), you get:\[A = (2 \times 1 - \frac{1}{2} - \frac{1}{4}) - (2 \times (-1) - \frac{1}{2} + \frac{1}{4}) = 4 - \frac{1}{2} = \frac{7}{2}.\]
04

Set Up the Integral for the Centroid (x-coordinate)

The x-coordinate of the centroid \( \bar{x} \) is found by:\[\bar{x} = \frac{1}{A} \int_{-1}^{1} x((2-x) - x^3)\, dx\].
05

Calculate the x-coordinate of the Centroid

Evaluate the integral to find \(\bar{x}\):\[\bar{x} = \frac{1}{\frac{7}{2}} \left[ \frac{x^3}{3} - \frac{x^4}{4} - \frac{x^5}{5} \right]_{-1}^{1}\]Calculating gives:\[\bar{x} = \frac{2}{7} \left[(\frac{1}{3} - \frac{1}{4} - \frac{1}{5}) - (-\frac{1}{3} + \frac{1}{4} + \frac{1}{5}) \right] = 0\].
06

Set Up the Integral for the Centroid (y-coordinate)

The y-coordinate of the centroid \( \bar{y} \) is given by:\[\bar{y} = \frac{1}{A} \int_{-1}^{1} \frac{(2-x) + x^3}{2} ((2-x) - x^3)\, dx\].
07

Calculate the y-coordinate of the Centroid

Evaluate the integral to find \(\bar{y}\):\[\bar{y} = \frac{1}{\frac{7}{2}} \left[ \frac{x^2}{2} - \frac{x^3}{3} - \frac{x^6}{6} \right]_{-1}^{1}\]Calculating gives:\[\bar{y} = \frac{2}{7} \left[(\frac{1}{2} - \frac{1}{3} - \frac{1}{6}) - (\frac{1}{2} - \frac{1}{3} - \frac{1}{6}) \right] = \frac{1}{2}\].
08

Conclusion

Thus, the centroid of the region bounded by the curves \(y=x^3\), \(x+y=2\), and \(y=0\) is at \( (0, \frac{1}{2}) \).

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.

Points of Intersection
Finding the points where curves intersect is crucial for determining the region's bounds. For the given curves, this involves solving for where they meet. Simply put, these
  • Identify where the graphs of the equations cross each other.
  • Give necessary limits for integration to find area and centroid.
To find intersections between the curves, substitute one equation into another. For example, insert \( y = x^3 \) into \( x + y = 2 \). By solving the resulting equation \( x + x^3 = 2 \), you discover the x-values \( x = 1 \) and \( x = -1 \). These solutions, when verified against the provided line equation \( y = 0 \), create points \((1,1)\) and \((-1,-1)\) in the coordinate system. Also, any intersections with the x-axis are noted as \((1,0)\) and \((-1,0)\). Knowing these points thoroughly sets the ground for the next steps.
Integral Setup
After identifying the intersection points, the next task is setting up the integral. Setting up an integral establishes the framework for calculating the regions' area, which is invaluable for centroid calculation.
  • The value found through integration is used in following steps to evaluate the centroid's coordinates accurately.
  • Boundaries for integration come from the intersection points.
For this problem, integrate from \(-1\) to \(1\) between the curves \(y = x^3\) and \(y = 2 - x\). The integral for area is:\[A = \int_{-1}^{1} ((2-x) - x^3) \, dx\]The expression "\((2-x) - x^3\)" signifies the vertical distance between the two curves. This integral is crucial as it provides the area \(A\) under the curves, an important part of finding the centroid's coordinates.
Coordinate System
Understanding the coordinate system helps map out the problem visually. It forms the skeletal framework that conveys how the curves interact in space.
  • A coordinate system provides orientation commonly defined by horizontal x-axis and vertical y-axis.
  • Important to figure out limits; determine meaningful bounding areas and lines.
In this situation, the solution illustrates graphing curves like \(y = x^3\), \(x + y = 2\), and intercept lines such as \(y = 0\). These intersections occur over specific x-values \(x = 1\) and \(x = -1\). The coordinate system clearly depicts how the curves intersect to form bounded regions. These regions are then used for integral limits, accounting for precisely where the curves overlap in the plane. Correct understanding aids in visualizing which sections matter for integration and how it impacts centroid calculation.
Calculus
Calculus serves as the backbone for solving problems involving curves and areas, particularly when finding centroids. Calculating here predominantly relies on integral calculus.
  • Used to find areas and centroids of regions bounded by curves.
  • Involves concepts like differential equations and integration techniques.
Integrals compute the area under the curves, providing insight into centroid values. Following initial integration to determine area:\[A = \int_{-1}^{1} (2 - x - x^3) \, dx\]Additional integrals help in pinpointing centroid coordinates. For example, the x-coordinate of the centroid is evaluated by:\[\bar{x} = \frac{1}{A} \int_{-1}^{1} x((2-x) - x^3) \, dx\]And the y-coordinate is:\[\bar{y} = \frac{1}{A} \int_{-1}^{1} \frac{(2-x) + x^3}{2} ((2-x) - x^3) \, dx\]These calculations unravel location insights of the centroid, crucial for understanding centers of mass or balance in geometry 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

Solve the equation \(y^{\prime}=x \sqrt{x^{2}+1} /\left(y e^{y}\right)\) and graph several members of the family of solutions (if your CAS does implicit plots). How does the solution curve change as the constant \(C\) varies?

A hawk flying at 15 \(\mathrm{m} / \mathrm{s}\) at an altitude of 180 \(\mathrm{m}\) accidentally drops its prey. The parabolic trajectory of the falling prey is described by the equation $$y=180-\frac{x^{2}}{45}$$ until it hits the ground, where \(y\) is its height above the ground and \(x\) is the horizontal distance traveled in meters. Calculate the distance traveled by the prey from the time it is dropped until the time it hits the ground. Express your answer correct to the nearest tenth of a meter.

A hole of radius \(r\) is bored through a cylinder of radius \(R>r\) at right angles to the axis of the cylinder. Set up, but do not evaluate, an integral for the volume cut out.

Use either a computer algebra system or a table of integrals to find the exact length of the arc of the curve \(x=\ln \left(1-y^{2}\right)\) that lies between the points \((0,0)\) and \(\left(\ln \frac{3}{4}, \frac{1}{2}\right)\)

Show how to approximate the required work by a Riemann sum. Then express the work as an integral and evaluate it. A leaky 10 -kg bucket is lifted from the ground to a height of 12 \(\mathrm{m}\) at a constant speed with a rope that weighs 0.8 \(\mathrm{kg} / \mathrm{m} .\) Initially the bucket contains 36 \(\mathrm{kg}\) of water, but the water leaks at a constant rate and finishes draining just as the bucket reaches the 12 -meter level. How much work is done?

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.