Limits of Integration of a Triangle

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Homework Help Overview

The discussion revolves around integrating a differential function over a triangular region defined by the vertices (0,0), (1,1), and (0,1). Participants are exploring the appropriate limits of integration for a double integral involving the function Z(x,y).

Discussion Character

  • Exploratory, Assumption checking, Mathematical reasoning

Approaches and Questions Raised

  • Participants are attempting to establish the limits of integration, with some suggesting that x should be between 0 and y, and y between 0 and 1. Others are questioning the correctness of these limits and discussing the integration of a sum involving dz.

Discussion Status

The discussion is active, with participants providing guidance on setting up the integrals and expressing uncertainty about the integration process. There are indications of differing interpretations regarding the integration of Z versus dZ, and some participants are reconsidering their approaches.

Contextual Notes

Some participants express confusion about the integration limits and the implications of terms with dx or dy being set to zero. There is also mention of a potential connection to integrals over the complex plane, which introduces additional complexity to the discussion.

Dopplershift
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Homework Statement


Suppose you have a Triangle with the vertices, (0,0) (1,1) and (0,1). Integrating along that path.

I have some differential function dZ where Z = Z(x,y)

Homework Equations

The Attempt at a Solution


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If I need to integrate, then I need to find the limits of integration. Am I correct with the following.

0 < x < y (x is between x and y)
0 < y < 1 (y is between 0 and 1).

I have attached my awful MS Paint drawing to demonstrate the triangle.
trainglethemrmo.png

http://[url=https://ibb.co/dgJzMF][PLAIN]https://image.ibb.co/bP8Naa/trainglethemrmo.png [/url][/PLAIN]
 
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This is a double integral, where the ends of the integrals need to change so that the integrals only cover the triangle. Start with a double integral with unknown ends and fill in the blanks:
??(∫??Z(x,y) dx)dy

I don't think that I should say more on a homework problem. Give it a try.
 
How to I integrate if the integral is a sum such as dz = y dx + (x+2y)dy ?

And are my limits of integration correct?
 
What are
Dopplershift said:
How to I integrate if the integral is a sum such as dz = y dx + (x+2y)dy ?
I may have misunderstood. Are you integrating Z or dZ?
And are my limits of integration correct?
What are your limits? I don't see them.
 
You didn't misunderstood, I mistyped, my apologies. It is dZ.

My limits I assumed are
0<y<1
0<x< y
 
You need to put the integrand into the formula of the integrals with correct limits on the integrals and keep track of which integration has dx≡0 or dy≡0.
 
FactChecker said:
You need to put the integrand into the formula of the integrals with correct limits on the integrals and keep track of which integration has dx≡0 or dy≡0.

That makes sense. Thank you! :)
 
Dopplershift said:
That makes sense. Thank you! :)
I'm having second thoughts. It doesn't seem right that terms with dx≡0 or dy≡0 would immediately disappear from the calculation. I would need to rethink this. You can try it with dx≡0 or dy≡0 and also with them constant and see if one approach makes more sense. Maybe someone more familiar with this can clarify.
 
Is this an integral over the complex plane? Do you have ##\mathop\int\limits_{T} f(z)dz##. If so, you can break it up into three integrals ##\mathop\int\limits_{T}=\mathop\int\limits_{T_1}+\mathop\int\limits_{T_2}+\mathop\int\limits_{T_3}## and for starters, if you let ##z=x+iy## over the complex plane then for example, you would have along the real axis: ##\mathop\int\limits_{T_1}f(x+iy)(dx+idy)=\mathop\int\limits_{a}^{b} f(x+iy)dx##. Right?
 

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