Finding the Relationship Between Volume and Surface Area of a Sphere

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Discussion Overview

The discussion revolves around finding the relationship between the volume and surface area of a sphere, specifically how to express surface area in terms of volume and vice versa. The scope includes mathematical reasoning and problem-solving related to geometry.

Discussion Character

  • Mathematical reasoning, Homework-related

Main Points Raised

  • One participant states the formulas for volume and surface area of a sphere and expresses difficulty in manipulating them to find the relationships.
  • Another participant suggests solving each formula for the radius (r) and substituting into the other formula to find the desired expressions.
  • A third participant reiterates the formulas and emphasizes the importance of proper mathematical notation, indicating that surface area is contained within the volume formula.
  • A later reply agrees with the method proposed by another participant but notes that it may become complicated without explicitly showing the variable r.

Areas of Agreement / Disagreement

Participants generally agree on the method of solving the problem by manipulating the formulas, but there is no consensus on the simplicity or clarity of the approach, as some express concern about the complexity involved.

Contextual Notes

There are unresolved aspects regarding the complete elimination of the variable r from the formulas, and participants have not reached a definitive solution.

david18
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The Volume and surface area of a sphere is 4/3πr^3 and 4πr^2 respectively. V=4/3πr^3 and S=4πr^2. Write a) S in terms of V and b) V in terms of S

Im stuck on this question... I write out similar base units and stuff but it doesn't seem to work, any help?

-The answer to part a is S=2^2/3 3^2/3 π^1/3 V^2/3
 
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Apparently what you have to is solve each formula for r, and then plug into the the other.

So to solve part a) first, solve your Volume formula for r. then plug that into r in your S formula.

Just do the opposite to solve part b.
 
david18 said:
The Volume and surface area of a sphere is 4/3πr^3 and 4πr^2 respectively. V=4/3πr^3 and S=4πr^2. Write a) S in terms of V and b) V in terms of S

Im stuck on this question... I write out similar base units and stuff but it doesn't seem to work, any help?

-The answer to part a is S=2^2/3 3^2/3 π^1/3 V^2/3

At least use grouping symbols properly if you do not have mathematical typesetting formatting. You intend to say
[tex]\[<br /> V = \left( {\frac{4}{3}} \right)\pi r^3 \quad S = 4\pi r^2 <br /> \][/tex]

You should see through inspection that S is actually contained in the formula for V.
[tex]\[<br /> V = \left( {\frac{1}{3}} \right)(4\pi r^2 )r = \frac{{Sr}}{3}<br /> \][/tex]
Right now, I do not yet see a way to completely eliminate 'r' from the formula. ...Should be possible though.
 
David18 has the right method. It will look a little messy but it will work. No need to bluntly show variable r.
 

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