Green's theorem with a scalar function

In summary, it is more efficient to parameterize the boundary into three curves and evaluate the integral of each instead of using Green's Theorem. The parameterization of the boundary is given by three curves going counterclockwise: x=t, y=t for 0≤t≤2, x=2cos(t), y=2sin(t) for π/4≤t≤π/2, and x=0, y=t for 2≥t≥0. Additionally, it is suggested to use LaTeX for better clarity and understanding.
  • #1
Amaelle
310
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Homework Statement
Look at the image
Relevant Equations
Green theorem
circuitation
Greetings!
My question is: is it possible to use the green theorem to compute the circulation while in presence of a scalar function ? I know how to solve by parametrising each part but just in case we can go faster? thank you!
1644760912541.png
 
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  • #2
I might b
Amaelle said:
Homework Statement:: Look at the image
Relevant Equations:: Green theorem
circuitation

Greetings!
My question is: is it possible to use the green theorem to compute the circulation while in presence of a scalar function ? I know how to solve by parametrising each part but just in case we can go faster? thank you!
View attachment 297061
I could be wrong, but I don't believe that Green's Theorem is a reasonable approach here. It seems much more straightforward to parameterize the boundary into three curves, and then evaluate the integral of each.

Going counterclockwise along ##\gamma##, we have
1. ##x = t, y = t, 0 \le t \le 2##
2. ##x = 2\cos(t), y= 2\sin(t), \pi/4 \le t \le \pi/2##
3. ##x = 0, y = t, 2 \ge t \ge 0##

BTW, your handwriting is not the easiest to read, particularly your shorthand abbreviations. Everything you wrote in longhand could be done using LaTeX, which would make it easier for us to understand.

For example:
Ex. 2: Compute ##\int_\gamma xy ds## where ##\gamma## is the parameterization of the boundary of
##D = \{(x, y) : x^2 + y^2 \le 2, x \ge 0, y \ge 0, y \ge x\}##
 
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Likes Amaelle
  • #3
Mark44 said:
I might b

I could be wrong, but I don't believe that Green's Theorem is a reasonable approach here. It seems much more straightforward to parameterize the boundary into three curves, and then evaluate the integral of each.

Going counterclockwise along ##\gamma##, we have
1. ##x = t, y = t, 0 \le t \le 2##
2. ##x = 2\cos(t), y= 2\sin(t), \pi/4 \le t \le \pi/2##
3. ##x = 0, y = t, 2 \ge t \ge 0##

BTW, your handwriting is not the easiest to read, particularly your shorthand abbreviations. Everything you wrote in longhand could be done using LaTeX, which would make it easier for us to understand.

For example:
Ex. 2: Compute ##\int_\gamma xy ds## where ##\gamma## is the parameterization of the boundary of
##D = \{(x, y) : x^2 + y^2 \le 2, x \ge 0, y \ge 0, y \ge x\}##
Thank you so much!
 

1. What is Green's theorem with a scalar function?

Green's theorem with a scalar function is a mathematical theorem that relates a line integral around a simple closed curve to a double integral over the region enclosed by the curve. It is used in vector calculus to solve problems involving the calculation of work done by a force field or the calculation of flux through a closed surface.

2. What is the significance of the scalar function in Green's theorem?

The scalar function in Green's theorem represents a quantity that varies over a region in space. It is used to calculate the work done by a force field or the flux through a closed surface. The scalar function can be thought of as a potential function that describes the behavior of the vector field.

3. How is Green's theorem with a scalar function different from Green's theorem with a vector field?

Green's theorem with a scalar function and Green's theorem with a vector field are similar in that they both relate a line integral to a double integral. However, Green's theorem with a scalar function involves a scalar quantity, while Green's theorem with a vector field involves a vector quantity. This means that the calculations and interpretations of the theorems are different.

4. What are the applications of Green's theorem with a scalar function?

Green's theorem with a scalar function has many applications in physics and engineering. It is commonly used to calculate the work done by a force field, the flux through a closed surface, or the circulation of a fluid. It is also used in electromagnetism, fluid mechanics, and heat transfer.

5. Is Green's theorem with a scalar function limited to two dimensions?

No, Green's theorem with a scalar function can be extended to three dimensions using the generalized Stokes' theorem. This theorem relates a surface integral to a volume integral and is used to solve problems involving the calculation of flux through a closed surface in three dimensions.

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