Triple Integral of z in a Wedge: Correcting Limits for y

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Homework Help Overview

The problem involves finding the triple integral of z over a region E defined by specific planes and a cylinder in the first octant. The original poster is focused on ensuring the correct setup of integration limits.

Discussion Character

  • Exploratory, Assumption checking, Problem interpretation

Approaches and Questions Raised

  • The original poster attempts to establish integration limits for x, y, and z but questions the correctness of their setup. Some participants suggest that the limits for z and y need to be reversed. Others express confusion about the reasoning behind the original limits and seek clarification.

Discussion Status

Participants are actively discussing the limits of integration, with some providing corrections and others reflecting on their own misunderstandings. There is a recognition that the limits for y may be particularly problematic, and suggestions are made to reconsider the order of integration.

Contextual Notes

There is mention of a negative result arising from the original limits, prompting further investigation into the correct setup. The discussion also includes a request for a diagram to aid in visualizing the region of integration.

evilpostingmong
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Homework Statement



Find the triple integral of z where E is bounded by the planes z=0 y=0 x+y=2 and the
cylinder z^2+y^2=1 in the first octant.

Homework Equations


The Attempt at a Solution


Just want to make sure that my setup is right. The limits of integration of x are 2 to 0,
for z, sqrt(1-y^2) to 0, and for y, 2-x to 0.
 
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Your z limits are not correct. It should go from 0 since it's bounded below by the xy plane to sqrt[1-y^2], limits of y should be reversed just like z.
 
The only reason why I integrated from sqrt(whatever) sorry lol is because the partial circle is "higher" than the xy plane.
Not trying to argue here, but can you explain why this is wrong? Srill don't quite get it.
 
Last edited:
Sorry for the double post, but I found that doing it my way gets a negative answer. Is that the reason? Oh and could someone please draw the diagram just so that I know what the graph of this should actually look like.
 
Upon closer inspection I realized that the limits for y are wrong. The upper limit for the y-integrand is either 2-x or sqrt[1-z^2] depending on where you draw the line parallel to the y-axis through the required volume. Try changing the order of the integration.

Since y is the problematic variable, let it be the last order of integration you perform. The limits for the other 2 variables are unambiguous.
 

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