Finding the Volume of Two Solids: A Cylindrical Approach

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Homework Help Overview

The problem involves finding the volume of a region defined by a cone and a cylinder, specifically the volume above the xy-plane, inside the cone described by z=7−√(x²+y²) and within the cylinder defined by x²+y²=4x.

Discussion Character

  • Exploratory, Assumption checking

Approaches and Questions Raised

  • The original poster attempts to use cylindrical coordinates to set up the volume integral but encounters difficulties with the bounds. Some participants question the limits for θ and suggest alternative ranges.

Discussion Status

Participants are actively discussing the bounds for θ in cylindrical coordinates, with some suggesting that the range should be from -π/2 to π/2. There is no explicit consensus yet, and the conversation is focused on clarifying these bounds.

Contextual Notes

The original poster has been working on the problem for several hours and is seeking guidance on the setup of the integral. There may be constraints related to the specific definitions of the cone and cylinder that are being examined.

tifa8
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Hello I need help for this problem, it has been 4 hours trying to do it

Homework Statement



Find the volume of the region of space above the xy-plane, inside the cone z=7−\sqrt{x^{2}+y^{2}} and inside the cylinder x^{2}+y^{2}=4x.

Homework Equations





The Attempt at a Solution



I tried to switch to cylindrical coordinates and I got

0\leq\theta\leq2\pi
0\leqr\leq4cos(\theta)
0\leqz\leq7-r

so,
V=\int^{2\pi}_{0}\int^{4cos(\theta)}_{0}\int^{7-r}_{0}rdzdrd\theta
which doesn't work...

thanks in advance
 
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I think you'll find that θ goes from -π/2 to π/2 .
 
thank you
 
SammyS said:
I think you'll find that θ goes from -π/2 to π/2 .

How did you find these bounds?
 

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