Proof of calculating area and volume

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    Area Proof Volume
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SUMMARY

The discussion centers on the mathematical concepts of area and volume, specifically regarding circles and spheres. The formulas for the perimeter of a circle (2πr), the area of a circle (πr²), and the volume of a sphere ((4/3)πr³) are established, with emphasis on the necessity of calculus for rigorous proofs. Participants debate the definitions of a circle and a disk, clarifying that a circle is a one-dimensional curve with zero area, while a disk is the two-dimensional area enclosed by that curve. The conversation highlights the importance of precise terminology in geometry.

PREREQUISITES
  • Understanding of basic geometry concepts, including circles and spheres.
  • Familiarity with calculus, particularly integration.
  • Knowledge of mathematical terminology, such as "circumference," "area," and "disk."
  • Ability to differentiate between one-dimensional and two-dimensional objects.
NEXT STEPS
  • Study the principles of integration in calculus to understand area and volume calculations.
  • Explore the distinction between geometric terms like "circle" and "disk" in mathematical literature.
  • Research the historical proofs of area and volume formulas, including those from ancient Greek mathematics.
  • Learn about Riemann sums and their application in calculating areas under curves.
USEFUL FOR

Mathematicians, educators, students studying geometry and calculus, and anyone interested in the precise definitions and proofs related to area and volume in geometry.

  • #31
Rogerio said:
Who is misleading people here?

According to you, if circle was just a curve, its area would be zero.

However, try google "area of a circle" and "area of a circumference", and see the difference. If it is not enough, google "area of a disk", too.

I find your arguments to be funny... :-p Sad but true... :-p

The circle is a curve.It has null area.It encloses a plain domain called DISK.

Daniel.
 
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  • #32
Rogerio said:
Who is misleading people here?

According to you, if circle was just a curve, its area would be zero.

However, try google "area of a circle" and "area of a circumference", and see the difference. If it is not enough, google "area of a disk", too.

"Circumference" is a number, not a set of points. The correct term for the set of points equi-distant from a given point is "circle" it has a circumference but its area is 0. The correct term for a the set of points bounded by a circle is "disk". It has non-zero area.

I did google on the terms you suggested. Of course, it is common to talk about the "area of a circle" when the strictly correct phrase should be "area of a disk". I notice that the hits on "area of a circumference" (there were only 4 as compared with thousands for "area of a circle" and "area of a disk") are all translations from a non-English source. I suspect that "circumference" is a mistranslation.
 

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