Graphs of solids of revolution

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Discussion Overview

The discussion revolves around the significance of drawing graphs of solids of revolution in mathematics, particularly in relation to integral calculus and engineering design. Participants explore the conceptual and practical aspects of representing these solids graphically, as well as the educational implications of understanding them.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested
  • Homework-related

Main Points Raised

  • One participant questions the importance of drawing graphs of solids of revolution, comparing it to the more established topic of conic sections.
  • Another participant suggests that while the graphs of solids of revolution may not be as significant on their own, they are crucial for understanding volumes in integral calculus and for sketching regions for double integrals.
  • A different viewpoint emphasizes the necessity of understanding solids of revolution in engineering design, indicating its practical applications.
  • Several participants request explanations on how to sketch these solids, indicating a desire for clarity on the methods involved.
  • One participant describes a method using 3D CAD systems to create solids of revolution, starting from a 2D cross-sectional shape and a central axis.
  • Another participant inquires about the possibility of creating these sketches on a semilog scale grid, suggesting a technical curiosity about different graphical representations.
  • There is a mention of the need for instruction from professors on sketching three-dimensional solids without modern technology, highlighting the educational aspect of the topic.

Areas of Agreement / Disagreement

Participants express differing views on the importance of drawing graphs of solids of revolution, with some emphasizing their practical applications in engineering and others questioning their standalone significance. The discussion remains unresolved regarding the overall importance and methods of representation.

Contextual Notes

Participants express uncertainty about the educational methods for sketching three-dimensional solids and the implications of using modern technology versus traditional techniques.

mech-eng
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Is drawing of graphs of solids of revolutions important topic of mathematics? This makes me remerber conic sections topic. Conic sections topic belongs to algebra and drawing their graphs is important. So where does solids of revolutions belong to? I know calculation of their volumes belongs to integral calculus but my question is little different.

Thank you.
 
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mech-eng said:
Is drawing of graphs of solids of revolutions important topic of mathematics? This makes me remerber conic sections topic. Conic sections topic belongs to algebra and drawing their graphs is important. So where does solids of revolutions belong to? I know calculation of their volumes belongs to integral calculus but my question is little different.
IMO, the graphs of solids of revolution isn't very important on its own. Most of the solids you get don't have their own names like the various conic sections do. As you note, the graphs of solids of revolution are used in the part of integral calculus that deals with volumes of various solids.

That said, if you don't know how to sketch a graph of a solid of revolution, you will have a hard time with the part of calculus that deals with these solids. And when you're working with double integrals, it is very important to be able to sketch a graph of the region over which integration is being done, as well as being able to sketch the solid whose volume the integral represents.
 
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An in depth understanding of how to work with solids of revolution is essential in many areas of engineering design work .
 
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It was done with one of the standard functions available in most 3D CAD systems .

Starts off as 2D drawing of the cross sectional shape required and a line showing where you want the central axis to be . The CAD system then sweeps the shape around to make the solid of revolution .

This is a very simple example . Many other 3D shape generating functions are available .
 
Nidum said:
View attachment 195579 It was done with one of the standard functions available in most 3D CAD systems .

Starts off as 2D drawing of the cross sectional shape required and a line showing where you want the central axis to be . The CAD system then sweeps the shape around to make the solid of revolution .

This is a very simple example . Many other 3D shape generating functions are available .
But can you do it on a grid that with a semilog scale? :oldbiggrin:
 
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mech-eng said:
Would you explain how you can do this?
Thank you.
With or without modern technology?
If without modern technology, how to make sketches of three-D solids is what your Calculus 2 & 3 professor should be showing your class. Hard to explain just using language in text. You need to draw three axes for the three dimensions, done on the 2-D writing surface.
 

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