Triple Integral in Cylindrical Coords

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Homework Help Overview

The problem involves constructing a triple integral in cylindrical coordinates to determine the volume of a cone defined by the equation r=z, with the height constrained by z=L. Participants are tasked with identifying the appropriate limits for integration in the specified format.

Discussion Character

  • Exploratory, Assumption checking

Approaches and Questions Raised

  • Participants discuss the interpretation of the limits for z and r, questioning how the infinite height implied by r=z can be reconciled with the finite height of L. There is an emphasis on visualizing the problem to clarify the bounds.

Discussion Status

The discussion is ongoing, with participants clarifying the limits of integration. Some have pointed out potential misunderstandings regarding the constraints of the problem, and there is a focus on ensuring the correct interpretation of the bounds.

Contextual Notes

There is a noted confusion regarding the limits of integration, particularly the interpretation of the inequalities related to z and r. Participants are encouraged to visualize the problem to aid in understanding the setup.

DTskkaii
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Homework Statement


Construct a triple integral in cylindrical coords to find the volume of the cone r=z, where the height (z value) is limited by z=L.
Should be in the form => {int[b,a] int[d,c] int[f,e]} (r) {dr dtheta dz}
(Sorry for weird formatting above, brackets purely to make terms more discernible)
Then evaluate using this order of integration to find volume.


Homework Equations


Volume of a cone => V=[(pi)(a)^2(L)]/3
In a cylindrical coord system, r=z describes an inverted cone of infinite height


The Attempt at a Solution


Currently working on an attempt, but if someone could help out with the understanding, that would be great. It doesn't immediately make a lot of sense to me.
i.e. r=z gives infinite height, but the volume is limited by L, so how do I find limits for that? Also can't see any immediate limits for theta in this situation.
 
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DTskkaii said:
r=z gives infinite height

What do you mean? The limits you are given are [itex]0 \ge z \ge L[/itex] and [itex]0 \ge r \ge z[/itex]. Everything is bounded here. Try drawing a picture to see why the limits are as they are.
 
clamtrox said:
What do you mean? The limits you are given are [itex]0 \ge z \ge L[/itex] and [itex]0 \ge r \ge z[/itex]. Everything is bounded here. Try drawing a picture to see why the limits are as they are.

I think you mean: [itex]0 \le z \le L[/itex] and [itex]0 \le r \le z[/itex]
 
sharks said:
I think you mean: [itex]0 \le z \le L[/itex] and [itex]0 \le r \le z[/itex]

Whoops! Indeed L>0 :)
 

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