Green's Theorem or Simple Line integral Evaluation

In summary, Green's theorem states that the area integral is equal to the line integral, so both methods can be used to evaluate the given line integral. The limits used in the attempt at a solution appear to be correct, and the line integral was also used to confirm the result.
  • #1
abrowaqas
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Homework Statement


Evaluate the following line integral

∫y^2 dx + x dy where C is the line segment joining the points (-5,-3) to (0,2) and is the arc of the parabola x= 4-y^2


Homework Equations



Green's Theorem
∫ Mdx + Ndy = ∫∫ (∂N/∂x - ∂M/∂y ) dy dx


The Attempt at a Solution



First of all i found the equation of line joining the above points ... which is x = y-2

the i started evaluate the integral by putting following limits i-e

∫( from y= -3 to y= 2) ∫( from x= y-2 to x=4-y^2) ( ∂N/∂x - ∂M/∂y ) dx dy

and i solved it further.

please guide me whether it is the correct method and my limits are correct or wrong or i have to go for line integral instead of green's th:

waiting for reply..
 
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  • #2
abrowaqas said:

Homework Statement


Evaluate the following line integral

∫y^2 dx + x dy where C is the line segment joining the points (-5,-3) to (0,2) and is the arc of the parabola x= 4-y^2


Homework Equations



Green's Theorem
∫ Mdx + Ndy = ∫∫ (∂N/∂x - ∂M/∂y ) dy dx


The Attempt at a Solution



First of all i found the equation of line joining the above points ... which is x = y-2

the i started evaluate the integral by putting following limits i-e

∫( from y= -3 to y= 2) ∫( from x= y-2 to x=4-y^2) ( ∂N/∂x - ∂M/∂y ) dx dy

and i solved it further.

please guide me whether it is the correct method and my limits are correct or wrong or i have to go for line integral instead of green's th:

waiting for reply..
Green's theorem says that area integral is equal to the line integral so either way works. You might also do the line integral to see if you get the same thing.
 
  • #3
yes i tried and got the same result.. thanks.
 

FAQ: Green's Theorem or Simple Line integral Evaluation

What is Green's Theorem?

Green's Theorem is a mathematical theorem that relates the line integral of a two-dimensional vector field over a closed curve to the double integral over the region enclosed by the curve. It is named after the mathematician George Green, who first stated the theorem in the 19th century.

What is the significance of Green's Theorem?

Green's Theorem is significant because it provides a powerful tool for solving line integrals and calculating areas in the plane. It also has many important applications in physics, engineering, and other fields.

How do you use Green's Theorem to evaluate a line integral?

To use Green's Theorem to evaluate a line integral, you first need to express the vector field in terms of its two component functions. Then, you can use the formula provided by Green's Theorem to calculate the line integral over the given closed curve.

Can Green's Theorem be applied to any closed curve?

No, Green's Theorem can only be applied to closed curves that are simple and smooth. This means that the curve cannot cross itself and its slope cannot be undefined at any point on the curve.

Are there any limitations to Green's Theorem?

Green's Theorem has certain limitations in terms of the type of integrals it can solve. It can only be used to evaluate line integrals over closed curves and cannot be applied to surfaces or curves that are not closed. Additionally, it is only applicable to two-dimensional vector fields.

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