Double integral, polar coordinates

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SUMMARY

The discussion focuses on evaluating the double integral \(\int\int_T (x^2+y^2) dA\) over a triangular region T defined by the vertices (0,0), (1,0), and (1,1). While polar coordinates were initially considered, it was concluded that using Cartesian coordinates is more appropriate due to the absence of circular symmetry in the region. The recommended approach involves determining the equations of the lines forming the triangle to establish the correct bounds for the double integral.

PREREQUISITES
  • Understanding of double integrals in calculus
  • Familiarity with polar coordinates and their application
  • Ability to derive equations of lines from given vertices
  • Knowledge of Cartesian coordinate systems
NEXT STEPS
  • Study the setup of double integrals in Cartesian coordinates
  • Learn how to derive line equations from points in a coordinate plane
  • Explore the conditions under which polar coordinates are advantageous
  • Practice evaluating double integrals over various geometric shapes
USEFUL FOR

Students in calculus, particularly those learning about double integrals and coordinate transformations, as well as educators seeking to clarify the application of polar versus Cartesian coordinates in integration.

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Homework Statement



Evaluate [tex]\int[/tex][tex]\int[/tex]T (x^2+y^2) dA, where T is the triangle with the vertices (0,0)(1,0)(1,1)

Homework Equations


The Attempt at a Solution



[tex]\int[/tex] d[tex]\theta[/tex] [tex]\int[/tex] r^3 dr

Thats how far I got, not really sure about boundries on r. First integrals boundrie should be 0 to pi/4. Is polar coordinates a good idea? Should I try some other change of variabel?

Help is appreciated

thanks!
 
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Polar coordinates can be made to work but they are not the natural way to work this problem. There are no circles involved in the region. Just set it up as a normal dydx integral.
 
I wouldn't do this in polar, though the x^2+y^2 makes it tempting...

Draw out the triangle and figure out the equations for the lines that make it up, use these lines as your bounds for your double integral.
 

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