What is the proof of d(x2)/dx = x?

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Discussion Overview

The discussion revolves around the proof of the derivative of the function \( x^2 \) with respect to \( x \). Participants explore different approaches to demonstrate that \( \frac{d}{dx}(x^2) = x \), engaging in mathematical reasoning and proofs.

Discussion Character

  • Mathematical reasoning
  • Debate/contested

Main Points Raised

  • One participant presents a proof that \( \frac{d}{dx}(x^2) = x \) by expressing \( x^2 \) as a sum of \( x \) added to itself \( x \) times, leading to the conclusion that the derivative is \( x \).
  • Another participant offers a different approach using summation notation, suggesting that the derivative results in \( 2x \) instead, which introduces a conflicting viewpoint.
  • A third participant reiterates the initial proof, expressing enthusiasm for the method presented.
  • One participant questions the validity of the ongoing discussion, implying that the arguments may not be serious or relevant.

Areas of Agreement / Disagreement

There is no consensus among participants; multiple competing views remain regarding the proof of the derivative of \( x^2 \). Some participants support the initial proof, while others challenge it with alternative reasoning.

Contextual Notes

The discussion includes differing interpretations of the derivative and the methods used to derive it, with unresolved mathematical steps and assumptions present in the arguments.

Ursole
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d(x^2)/dx = x

d(x2)/dx = x

PROOF:

d(x2)/dx = d(x + x + x + ... (x times))/dx

= d[x]/dx + d[x]/dx + d[x]/dx... (x times)

= 1 + 1 + 1 + ... (x times)

= x

QED

:wink:
 
Last edited:
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[tex]\frac{d}{dx}\sum_{i=1}^{x}x=(\frac{d}{dx}\sum_{i=1}^{x}1)x+\sum_{i=1}^{x}\frac{dx}{dx}=x+x=2x[/tex]
 
Ursole said:
d(x2)/dx = x

PROOF:

d(x2)/dx = d(x + x + x + ... (x times))/dx

= d[x]/dx + d[x]/dx + d[x]/dx... (x times)

= 1 + 1 + 1 + ... (x times)

= x

QED
What a new invention ! <<:thumbsUp:>>
 

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