Re: Division by zero

W dniu 04.02.2025 o 10:13, Mikko pisze:

On 2025-02-04 07:36:34 +0000, Thomas Heger said:
 

Am Montag000003, 03.02.2025 um 16:51 schrieb Mikko:

On 2025-02-03 07:56:53 +0000, Thomas Heger said:
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Am Sonntag000002, 02.02.2025 um 10:30 schrieb Mikko:
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Hi NG
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I'm actually not really certain, but found an error in Einstein's 'On the electrodynamics of moving bodies' which is quite serious.
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See page six, roughly in the middle:
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There we find an equation, which says this:
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∂τ/∂y= 0

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Do you mean on page 899 (9th page of the article) in §3?
The operation is not division but a partial derivative.

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You should answer this question. It is not useful to talk without telling
what you are talking about.
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I'm referring to the English translation, which can be found here
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https://www.fourmilab.ch/etexts/einstein/specrel/www/
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The English pdf version has other page numbers than the original article.
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But in a way, these original page numbers are also possible as reference.
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But unfortunately I have here only the English version (the German I have on a different computer).
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So I have to tell you the page from the English version or make the meant part available to you by other means.
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So, § 3 was meant and roughly the middle, which can be found on page 6 of the English pdf version.
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And you are absolutely right, that a partial derivative was meant.
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The problem was: of which function was a partial derivative meant?

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He obviously means the function needed to determine τ. It does not matter
whether he means the function from x, y, z, t or x', y, z, t as ∂/∂y is
the same in both cases.

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There ain't no thing as 'obviously'.

 Of course there is.
 

If an author doesn't write, what he has in mind, the reader is requirred to guess. And the result of such a process is by no means 'obvious'.

 What the author has in mind is not relevant. Relevant is what physicists
at the time understood the text to say.
 

Einstein used τ for three different types of mathematical objects:
a value τ (meaning: time in k)
a function τ (a coordinate transformation between K and k)
as function value τ of that function τ.

 meaning: time in k
 

Therefor it would requirre some brains to find out, which one was actually meant.

 It is reasonable to assume that the intended readers had brains.
 

Correct would have been to make the type explicit, e.g. by different fonts.

 It is sufficient that the target audence can understand the emaning of the
text.

Stop fucking, trash. If the audience was able to
comprehend what the idiot mumbled they would ROTFL.
It was not even consistent.