Green's Theorem with a circle not centered at the origin.

In summary, the integral F dot dr over the region R, where C is the boundary of the region and is oriented so that the region is on the left when the boundary is traversed in the direction of its orientation, is equal to -128π.
  • #1
kana021693
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Problem: Evaluate Integral F dot dr, where C is the boundary of the region R and C is oriented so that the region is on the left when the boundary is traversed in the direction of its orientation.
F(x,y)=(e^(-x)+3y)i+(x)j
C is the boundary of the region R inside the circle x^2+y^2=16 and outside the circle x^2-2x+y^2=3

Homework Equations


Integral F dot dr=DOuble integral over the region R, (dg/dx-df/dy)dA


The Attempt at a Solution


I started by completing the square of that circle that is not centered at the origin, and got (x-1)^2+y^2=4. So now I know the inner region's boundary is a circle of radius 2 centered at (1,0).
Also, I got the double integral over x^2+y^2=16 , Double integral 0to 2pi, 0 to 4 (-2)r dr dtheta and got -32pi.
But I don't know what to do from here. The circle x^2-2x+y^2=3 is giving me a hard time. Can you tell me how to do the rest of this problem?
 
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  • #2
The solution to this problem is as follows: First, complete the square on the second circle to get (x-1)^2+y^2=4. Then, set up the double integral over the region R such that the inner boundary is the circle of radius 2 centered at (1,0) and the outer boundary is the circle of radius 4 centered at the origin. The double integral over R is then given by: Double integral 0to 2pi, 0 to 2 (-2e^(-r cos(theta))r - 6r sin(theta)) r dr dthetaEvaluating this double integral yields a result of -128π.
 

Related to Green's Theorem with a circle not centered at the origin.

1. What is Green's Theorem?

Green's Theorem is a mathematical theorem that relates the line integral around a simple closed curve to a double integral over the region enclosed by the curve. It is a fundamental tool in vector calculus and is used to solve various problems in physics and engineering.

2. How does Green's Theorem apply to a circle not centered at the origin?

Green's Theorem can still be applied to a circle not centered at the origin, as long as the curve is simple and closed. The theorem states that the line integral around the curve is equal to the double integral over the region enclosed by the curve, regardless of the position of the circle.

3. What is the formula for Green's Theorem with a circle not centered at the origin?

The formula for Green's Theorem with a circle not centered at the origin is ∮C(Mdx + Ndy) = ∬R((∂N/∂x) - (∂M/∂y)) dA, where C is the simple closed curve, R is the region enclosed by the curve, and M and N are functions of x and y.

4. Can Green's Theorem be used to find the area of a region enclosed by a circle not centered at the origin?

Yes, Green's Theorem can be used to find the area of a region enclosed by a circle not centered at the origin. By choosing M = 0 and N = x, the double integral can be simplified to just the area of the region, making it a useful tool for finding areas of irregular shapes.

5. How is Green's Theorem related to other theorems in vector calculus?

Green's Theorem is closely related to other fundamental theorems in vector calculus, such as the Divergence Theorem and Stokes' Theorem. All three theorems relate different types of integrals to each other, providing powerful tools for solving problems in mathematics, physics, and engineering.

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