Evaluating an Integral in Polar Coordinates

In summary, an integral in polar coordinates is a mathematical operation used to find the area under a curve in a polar coordinate system. It involves evaluating the integral expression using polar limits of integration and differential elements. Using polar coordinates can be advantageous for certain curves, but can also be more complicated to visualize and understand compared to Cartesian coordinates. Practical applications of evaluating an integral in polar coordinates include calculating moments of inertia, finding volumes of solids, and determining work done by forces along curved paths.
  • #1
PsychonautQQ
784
10

Homework Statement


Evalutate the double integral sin(x^2+y^2)dA between the region 1≥x^2+y^2≥49



The Attempt at a Solution


so r^2 = x^2 + y^2
dA = rdrdθ

so I can turn this into
double integral sin(r^2)rdrdθ
where the inner integral integrated with respect to dr goes from 1 to 7?
and then what are the parameters for integrating with respect to θ? 0 to 2pi?
Does this look correct?
 
Physics news on Phys.org
  • #2
To clarify your question: it gives no boundary conditions for your [itex]\theta[/itex] axis, so you are integrating over a disk of radius 7 (starting at 1). So yes your integral seems correct.
 

1. What is an integral in polar coordinates?

An integral in polar coordinates is a mathematical operation used to find the area under a curve in a polar coordinate system. It involves evaluating the integral expression, which represents the sum of infinitely many small areas under the curve, and finding its value.

2. How is an integral evaluated in polar coordinates?

To evaluate an integral in polar coordinates, the integral expression is converted into polar form by substituting x and y values with their polar coordinate equivalents. Then, the integral is evaluated using the polar coordinate system, which involves using the polar limits of integration and the polar equivalents of the differential element, dx and dy.

3. What are the advantages of using polar coordinates to evaluate an integral?

Using polar coordinates to evaluate an integral can be advantageous in certain scenarios. For example, when the curve being integrated is better described using polar coordinates, such as circles or spirals. Additionally, polar coordinates can simplify the integral expression, making it easier to evaluate.

4. What are the limitations of using polar coordinates to evaluate an integral?

One limitation of using polar coordinates to evaluate an integral is that it can be more complicated to visualize and understand compared to Cartesian coordinates. Additionally, the conversion from Cartesian to polar coordinates can sometimes result in more complex integral expressions, making them more difficult to evaluate.

5. What are some practical applications of evaluating an integral in polar coordinates?

Evaluating an integral in polar coordinates has many practical applications in fields such as physics, engineering, and mathematics. Some examples include calculating the moment of inertia of a rotating object, finding the volume of a solid with a curved boundary, and determining the work done by a force acting along a curved path.

Similar threads

  • Calculus and Beyond Homework Help
Replies
3
Views
276
Replies
4
Views
904
  • Calculus and Beyond Homework Help
Replies
24
Views
1K
  • Calculus and Beyond Homework Help
Replies
5
Views
1K
  • Calculus and Beyond Homework Help
Replies
1
Views
997
  • Calculus and Beyond Homework Help
Replies
2
Views
859
  • Calculus and Beyond Homework Help
Replies
3
Views
952
  • Calculus and Beyond Homework Help
Replies
1
Views
493
  • Calculus and Beyond Homework Help
Replies
6
Views
1K
  • Calculus and Beyond Homework Help
Replies
7
Views
1K
Back
Top