How to Attempt a Path Integral Problem with Green's Theorem?

In summary, the region bounded by the curves y= 5x2 and y=12.x is only affected by the path integrals taken in the anti clockwise direction.
  • #1
aleena
2
0

Homework Statement


A region R is bounded by the curves y = 12.x and y=5.x^2
If I = (5/12).x^2 .y i + (y/12.x) j

find the contribution to the line integral
Integral I.dl = Integral (I(x) dx + I(y) dy)

taken in the anti clockwise direction with respect to the region R along the curve y = 5.x^2 only.

ANSWER: 52.376

Homework Equations



Green's Theorem.

The Attempt at a Solution


I been working on this problem for almost a day can someone please tell me the right way to attempt this problem
 
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  • #2
Are you required to use Green's theorem to solve this? Because if you don't you can evaluate the line integral directly without having to use the closed curve line integral minus the line integral constribution along the straight line.
 
  • #3
If you have "been working on this problem for almost a day", why don't you show us what you have done in that day? This looks like a pretty basic path-integral problem.

Go back to the original definition of line integral:

Write x and y in terms of a single parameter. Since here the curve is defined by a function of y, y= 5x2, you can use x itself as the parameter. With y= 5x2, what is dy in terms of dx? What is I(x,y) in terms of x only?

By the way, your notation is confusing. I(x,y) is a function of two variables. I(x) and I(y) make no sense. Do you mean the x component and y component if I(x,y)?
Also, is "y/12.x" supposed to be "y/(12x)" or "(y/12)x"?
 
  • #4
HallsofIvy said:
If you have "been working on this problem for almost a day", why don't you show us what you have done in that day? This looks like a pretty basic path-integral problem.

Go back to the original definition of line integral:

Write x and y in terms of a single parameter. Since here the curve is defined by a function of y, y= 5x2, you can use x itself as the parameter. With y= 5x2, what is dy in terms of dx? What is I(x,y) in terms of x only?

By the way, your notation is confusing. I(x,y) is a function of two variables. I(x) and I(y) make no sense. Do you mean the x component and y component if I(x,y)?
Also, is "y/12.x" supposed to be "y/(12x)" or "(y/12)x"?

I have attached original file, my working outs are all on paper I don't have a scanner or else i would have attached them as well.
 

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  • #5
HallsofIvy said:
If you have "been working on this problem for almost a day", why don't you show us what you have done in that day? This looks like a pretty basic path-integral problem.

Go back to the original definition of line integral:

Write x and y in terms of a single parameter. Since here the curve is defined by a function of y, y= 5x2, you can use x itself as the parameter. With y= 5x2, what is dy in terms of dx? What is I(x,y) in terms of x only?

By the way, your notation is confusing. I(x,y) is a function of two variables. I(x) and I(y) make no sense. Do you mean the x component and y component if I(x,y)?
Also, is "y/12.x" supposed to be "y/(12x)" or "(y/12)x"?

i am also having problem to do path integrate which is similar problem. Could you please show me how to attempt the question ! thanks
 

What is a line integral in vector calculus?

A line integral, also known as a path integral, is a mathematical concept in vector calculus that involves integrating a scalar or vector function along a given curve or path. It is used to calculate quantities such as work, flux, and circulation in a vector field.

What is the difference between a line integral and a regular integral?

The main difference between a line integral and a regular integral is that a line integral involves integrating along a specified curve or path, while a regular integral involves integrating over a specific interval. Line integrals also take into account the direction of the curve, which can affect the resulting value.

How is a line integral calculated?

A line integral is calculated by first parameterizing the given curve or path using a parameter t. This transforms the curve into a function of t, which can then be integrated with respect to t. The resulting integral can be evaluated using techniques such as substitution or integration by parts.

What is the significance of the direction of the curve in a line integral?

The direction of the curve in a line integral is important because it affects the resulting value of the integral. If the curve is traversed in the opposite direction, the resulting integral will have a negative value. This is because the direction of the curve determines the orientation of the vector field being integrated over.

What are some real-world applications of line integrals in vector calculus?

Line integrals have many real-world applications, such as calculating work done by a force, determining the flow of a fluid through a curve, and calculating the potential difference between two points in an electric field. They are also used in physics, engineering, and other fields to solve problems involving motion, energy, and other physical quantities.

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