Sketch & Evaluate Region of Integration

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Homework Help Overview

The discussion revolves around sketching a region of integration and rewriting an integral in a different order. The subject area includes multivariable calculus, specifically focusing on integration in three dimensions.

Discussion Character

  • Exploratory, Assumption checking, Problem interpretation

Approaches and Questions Raised

  • Participants discuss the correct representation of the region of integration, questioning the original poster's sketch and the axes labeling. There are attempts to clarify the shape of the base of the region and the implications of the coordinate system used.

Discussion Status

Some participants have provided corrections and suggestions regarding the sketch, indicating a productive exchange of ideas. There is ongoing clarification about the axes and the shape of the region, but no consensus has been reached on the final representation.

Contextual Notes

There are references to potential misunderstandings regarding the coordinate system and the shape of the region, which may affect the interpretation of the integral setup. The original poster's sketch and corrections are noted as points of contention.

korr2221
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http://qaboard.cramster.com/Answer-Board/Image/cramster-equation-20081241616516336400421111250005486.gif

Homework Statement


1. Sketch the region of integration
2. Rewrite the integral in the order: dydxdz
3. Evaluate the integral (using either order)The attempt at a solution

Attached.

alternative link:

http://www.yourfilelink.com/get.php?fid=476767
 

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corrections made about my sketch

alternative:
http://www.yourfilelink.com/get.php?fid=476770
 

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You seem to have draw the base as a rectangle when it should be a triangle but since you have not marked which axis is the x-axis, which the y-axis, and which the z-axis, I can't be sure.
If you intended the axis on which "2" is marked to be the x-axis, then you have drawn a "left handed" coordinate system when the standard is "right handed"- curling the fingers of your right hand from the x-axis to the y-axis, your thumb should point in the direction of the positive z-axis.

Since the "outermost" integral is from x= 0 to x= 2, mark vertical lines at x= 0 and x= 2 on the xy-plane.

Since the second integral is from y= 0 to y= x, draw the line y= x on the xy-plane. That gives a triangle with vertices at (0,0), (2,0), and (2,2).

Since "innermost" integral is from z= 0 to z= 2- x, that triangle is the base and the top of the region is the plane z= 2-x. That slopes downward from x=0, z= 2 on the left to x=2, z= 0 on the right.
 
HallsofIvy said:
You seem to have draw the base as a rectangle when it should be a triangle but since you have not marked which axis is the x-axis, which the y-axis, and which the z-axis, I can't be sure.
If you intended the axis on which "2" is marked to be the x-axis, then you have drawn a "left handed" coordinate system when the standard is "right handed"- curling the fingers of your right hand from the x-axis to the y-axis, your thumb should point in the direction of the positive z-axis.

Since the "outermost" integral is from x= 0 to x= 2, mark vertical lines at x= 0 and x= 2 on the xy-plane.

Since the second integral is from y= 0 to y= x, draw the line y= x on the xy-plane. That gives a triangle with vertices at (0,0), (2,0), and (2,2).

Since "innermost" integral is from z= 0 to z= 2- x, that triangle is the base and the top of the region is the plane z= 2-x. That slopes downward from x=0, z= 2 on the left to x=2, z= 0 on the right.

uh, i believe you aren't looking at the corrections, the first one, in the first page is something else... sorry
 

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