Exhaustion Methods Explained: Sum of Areas of Outer & Inner Rectangles

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Discussion Overview

The discussion revolves around the exhaustion methods for calculating the sum of areas of outer and inner rectangles as presented in Apostol's volume 1. Participants explore the mathematical expressions involved and seek clarification on the value of "k" in the context of inner rectangle area sums.

Discussion Character

  • Exploratory, Technical explanation, Conceptual clarification

Main Points Raised

  • One participant questions the expression for the sum of the areas of outer rectangles and seeks clarification on why the value of "k" for the inner area sum goes to n-1.
  • Another participant suggests that the interior rectangles cannot include the value at b, implying that "k" must be less than n to avoid cancellation, although they express uncertainty about their reasoning.
  • A third participant provides a formula for the sum of squares, indicating a mathematical relationship but expresses doubt about the meaning of "k" without further context.
  • A later reply indicates that the original poster has resolved their question independently.

Areas of Agreement / Disagreement

The discussion shows some uncertainty regarding the interpretation of "k" and its role in the area sums. While one participant finds a resolution, the overall understanding of "k" remains unclear among others.

Contextual Notes

Participants do not clarify what "k" specifically represents, which may affect the understanding of the area sums. The discussion also reflects a lack of consensus on the reasoning behind the choice of n-1 for the inner rectangles.

andrewkg
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Well if anyone has read Apostol's vol 1. Can anyone explain in the beginingthe sum of the areas of the outer rectangles is (b^3/n^3)(k^2) or
(b^3/n^3)(1^2+2^2+3^2…+n^2)

And the area of the inner rectangles and (b^3/n^3)(1^2+2^2+3^2…+(n-1)^2)

What I would like to know is why does the value of k for the inner area sum goes to n-1
Thank you
 
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Oh yeah. My idea was that the interior rectangles cannot have a value directly at b so the value of k must be under the of n so n doesn't cancek out. Although this woukd not occur anyways because the value of n on the bottom is n^3 and the value of k on tome is only squared. Honestly though I don't have a good idea. I tryed it graphically on my own paper I got lost with what I was doing.
 
You should know that
1^2+ 2^2+ 3^2+ \cdot\cdot\cdot+ n^2= \frac{n(n+1)(2n+1)}{6}

As to what happens to the "k", I doubt if anyone can answer because you have not said what "k" represents.
 
Nvm I got it. Thanks though
 

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