Using Green's Theorem to evaluate the line integral.

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Homework Help Overview

The discussion revolves around applying Green's Theorem to evaluate a line integral defined over a triangular path connecting the points (-1,0), (1,0), and (0,1). Participants are exploring how to set up the bounds for the double integral that arises from the theorem.

Discussion Character

  • Exploratory, Mathematical reasoning, Problem interpretation

Approaches and Questions Raised

  • Participants discuss the appropriate bounds for the integral, with one participant suggesting that the triangle can be divided into two regions based on the x-values. Questions arise about how to define the upper and lower limits of integration for each segment.

Discussion Status

There is an ongoing exploration of how to correctly set the bounds for the integral. Some guidance has been provided regarding the limits based on the geometry of the triangle, and participants are clarifying their understanding of the relationships between the points and the equations of the lines forming the triangle's sides.

Contextual Notes

Participants are working within the constraints of the problem as stated, specifically focusing on the triangular region defined by the given points and the implications of using Green's Theorem.

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Homework Statement



Green's Theorem to evaluate the line following line integral, oriented clockwise.
∫xydx+(x^2+x)dy, where C is the path though points (-1,0);(1,0);(0,1)

Homework Equations


Geen's theorem: ∫F°DS=∫∫ \frac{F_2}{δx}-\frac{F_1}{δy}


The Attempt at a Solution


attachment.php?attachmentid=53123&stc=1&d=1353355503.jpg


What would I use for the bounds. I know it has to do with the triangle. But how would I find the bounds?
 

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You've pretty much written it down yourself: the lower limit is clearly y= 0. The upper limits are those two other sides of the triangle: if x< 0, y= x+ 1, if x> 0, y= -x+1.
So you can divide this into two sets of integrals: for x from -1 to 1, y goes from 0 to x+ 1, for x from 0 to 1, y goes from 0 to 1- x.
 
Thanks... Halls. I wasn't sure what to do, but I understand now. It's like you've divided the triangle into 2 pieces.
 
And made both of the equations x+1 and 1-x satisfy their respective points... but I think the upper and lower bound of x+1 is -1 and 0 respectively since it goes from 0 to satisfy point (0,1) and -1 for (-1,0) and goes from the first point to the other.
 

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