Use a change to polar coordinates to compute the double integral S S dA, where R is R the region between two circles centered at the origin with radii a and b, where 0 < a < b.

Advanced Engineering Mathematics
10th Edition
ISBN:9780470458365
Author:Erwin Kreyszig
Publisher:Erwin Kreyszig
Chapter2: Second-order Linear Odes
Section: Chapter Questions
Problem 1RQ
icon
Related questions
Question
### Problem Statement

**Topic: Polar Coordinates and Double Integration**

Use a change to polar coordinates to compute the double integral 

\[ \iint_{R} \frac{y^2}{x^2 + y^2} \, dA, \]

where \( R \) is the region between two circles centered at the origin with radii \( a \) and \( b \), where \( 0 < a < b \). 

### Detailed Explanation

**Transforming to Polar Coordinates:**

In polar coordinates, any point \((x, y)\) in the Cartesian plane can be represented as \((r \cos \theta, r \sin \theta)\), where \( r \) is the radius, or the distance from the origin, and \( \theta \) is the angle formed with the positive \(x\)-axis.

The region \( R \) described is the annular region between two circles with radii \( a \) and \( b \). This can be mathematically expressed as:

\[ a \leq r \leq b,\]
\[ 0 \leq \theta < 2\pi. \]

**Integrand in Polar Coordinates:**

Given the integrand \(\frac{y^2}{x^2 + y^2}\):
\[ y = r \sin \theta, \]
\[ x^2 + y^2 = r^2. \]

Thus, the given integrand in polar coordinates becomes:
\[ \frac{y^2}{x^2 + y^2} = \frac{(r \sin \theta)^2}{r^2} = \sin^2 \theta. \]

The differential element \( dA \) in polar coordinates is \( r \, dr \, d\theta \).

**Integral Transformation:**

The double integral can be transformed as:
\[ \iint_{R} \frac{y^2}{x^2 + y^2} \, dA = \int_{0}^{2\pi} \int_{a}^{b} \sin^2 \theta \, r \, dr \, d\theta. \]

Here, the limits of integration for \( r \) are from \( a \) to \( b \), and for \( \theta \) are from \( 0 \) to \( 2\pi \).

### Detailed Steps to Solve the Integral:

1
Transcribed Image Text:### Problem Statement **Topic: Polar Coordinates and Double Integration** Use a change to polar coordinates to compute the double integral \[ \iint_{R} \frac{y^2}{x^2 + y^2} \, dA, \] where \( R \) is the region between two circles centered at the origin with radii \( a \) and \( b \), where \( 0 < a < b \). ### Detailed Explanation **Transforming to Polar Coordinates:** In polar coordinates, any point \((x, y)\) in the Cartesian plane can be represented as \((r \cos \theta, r \sin \theta)\), where \( r \) is the radius, or the distance from the origin, and \( \theta \) is the angle formed with the positive \(x\)-axis. The region \( R \) described is the annular region between two circles with radii \( a \) and \( b \). This can be mathematically expressed as: \[ a \leq r \leq b,\] \[ 0 \leq \theta < 2\pi. \] **Integrand in Polar Coordinates:** Given the integrand \(\frac{y^2}{x^2 + y^2}\): \[ y = r \sin \theta, \] \[ x^2 + y^2 = r^2. \] Thus, the given integrand in polar coordinates becomes: \[ \frac{y^2}{x^2 + y^2} = \frac{(r \sin \theta)^2}{r^2} = \sin^2 \theta. \] The differential element \( dA \) in polar coordinates is \( r \, dr \, d\theta \). **Integral Transformation:** The double integral can be transformed as: \[ \iint_{R} \frac{y^2}{x^2 + y^2} \, dA = \int_{0}^{2\pi} \int_{a}^{b} \sin^2 \theta \, r \, dr \, d\theta. \] Here, the limits of integration for \( r \) are from \( a \) to \( b \), and for \( \theta \) are from \( 0 \) to \( 2\pi \). ### Detailed Steps to Solve the Integral: 1
Expert Solution
trending now

Trending now

This is a popular solution!

steps

Step by step

Solved in 2 steps with 14 images

Blurred answer
Knowledge Booster
Double Integration
Learn more about
Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, advanced-math and related others by exploring similar questions and additional content below.
Recommended textbooks for you
Advanced Engineering Mathematics
Advanced Engineering Mathematics
Advanced Math
ISBN:
9780470458365
Author:
Erwin Kreyszig
Publisher:
Wiley, John & Sons, Incorporated
Numerical Methods for Engineers
Numerical Methods for Engineers
Advanced Math
ISBN:
9780073397924
Author:
Steven C. Chapra Dr., Raymond P. Canale
Publisher:
McGraw-Hill Education
Introductory Mathematics for Engineering Applicat…
Introductory Mathematics for Engineering Applicat…
Advanced Math
ISBN:
9781118141809
Author:
Nathan Klingbeil
Publisher:
WILEY
Mathematics For Machine Technology
Mathematics For Machine Technology
Advanced Math
ISBN:
9781337798310
Author:
Peterson, John.
Publisher:
Cengage Learning,
Basic Technical Mathematics
Basic Technical Mathematics
Advanced Math
ISBN:
9780134437705
Author:
Washington
Publisher:
PEARSON
Topology
Topology
Advanced Math
ISBN:
9780134689517
Author:
Munkres, James R.
Publisher:
Pearson,