Limits of Integration of a Triangle

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SUMMARY

The discussion focuses on determining the limits of integration for a double integral over a triangle defined by the vertices (0,0), (1,1), and (0,1). The correct limits of integration are established as 0 < y < 1 and 0 < x < y. Participants clarify the integration of the differential function dZ, where Z = Z(x,y), and discuss the implications of integrating with respect to dx and dy. The conversation emphasizes the importance of correctly setting the limits to ensure the integral accurately represents the area of the triangle.

PREREQUISITES
  • Understanding of double integrals in calculus
  • Familiarity with the concept of limits of integration
  • Knowledge of differential functions and notation
  • Basic geometry of triangles in the Cartesian plane
NEXT STEPS
  • Study the process of setting limits for double integrals in various geometric shapes
  • Learn about the application of Green's Theorem in relation to line integrals
  • Explore the integration of complex functions over specified paths
  • Review the properties of differential forms and their integration
USEFUL FOR

Students studying calculus, particularly those focusing on multivariable integration, as well as educators seeking to clarify concepts related to double integrals and geometric interpretations in calculus.

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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