Finding the Correct Parameterization for Line Integral

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SUMMARY

The discussion focuses on solving a line integral problem from Stewart's calculus textbook, specifically Q 3 from chapter 16.4. The integral involves the function Int xy dx + x^2*y^3 dy over a triangular path defined by the vertices (0,0), (1,0), and (1,2). The user struggles with parameterizing the vertical line segment from (1,0) to (1,2) and integrating correctly, ultimately realizing that the dx term becomes irrelevant since x is constant along that segment.

PREREQUISITES
  • Understanding of line integrals in vector calculus
  • Familiarity with parameterization of curves
  • Knowledge of Green's Theorem
  • Basic calculus skills, including integration techniques
NEXT STEPS
  • Review the concept of line integrals in vector fields
  • Practice parameterizing different types of line segments
  • Study the application of Green's Theorem for line integrals
  • Explore examples of integrating functions over triangular paths
USEFUL FOR

Students studying calculus, particularly those tackling line integrals and vector fields, as well as educators looking for examples of parameterization techniques.

Darkmisc
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Homework Statement



I'm attempting Q 3 from ch 16.4 of Stewart (p 1060).

We are required to find the line integral where C is the triangle with vertices (0,0), (1,0) and (1,2).

The line integral is

Int xy dx + x^2*y^3 dy




Homework Equations





The Attempt at a Solution



I'm having trouble parametizing the vertical line between (1,0) and (1,2).

I'd let y = 2t and x = 1, but got the wrong final answer. I suspect it's because line (1,0) to (1,2) was incorrectly expressed.

I then wanted to integrate in terms of dy, with terminals for y of 0 and 2, and parametizing y in terms of y, but where does that leave the dx in the first part of the equation?

I imagine it would be easier to use Green's Theorem, but the question specifically requires the use of line integrals.
 
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Darkmisc said:

Homework Statement



I'm attempting Q 3 from ch 16.4 of Stewart (p 1060).

We are required to find the line integral where C is the triangle with vertices (0,0), (1,0) and (1,2).

The line integral is

Int xy dx + x^2*y^3 dy

Homework Equations


The Attempt at a Solution



I'm having trouble parametizing the vertical line between (1,0) and (1,2).

I'd let y = 2t and x = 1, but got the wrong final answer. I suspect it's because line (1,0) to (1,2) was incorrectly expressed.

I then wanted to integrate in terms of dy, with terminals for y of 0 and 2, and parametizing y in terms of y, but where does that leave the dx in the first part of the equation?

I imagine it would be easier to use Green's Theorem, but the question specifically requires the use of line integrals.
Both parameterizations would work, but you haven't provided enough detail for us to see where you went wrong. In either case, x is a constant, so the dx term drops out.
 

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