Re: Division by zero

On 2025-02-01 08:14:08 +0000, Thomas Heger said:

Hi NG
 I'm actually not really certain, but found an error in Einstein's 'On the electrodynamics of moving bodies' which is quite serious.
  See page six, roughly in the middle:
 There we find an equation, which says this:
 ∂τ/∂y= 0

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

Now, 'tau' is a time belonging to the moving system k.

Yes, but it is also a number that is computed from coordinates of K.

This system k moves along the x-axis of system K with velocity v, while x- and xsi-axis coincide and etha- and y axis remain parallel.
 In other words v_y is permanently zero,

Yes,

 or: ∂y=0.

No. ∂y is not a number but a part of an operator. There are points with
different values of y and ∂/∂y refers to a line where t, x, and z (but not
y) have the same value at every point.
See https://en.wikipedia.org/wiki/Partial_derivative
--
Mikko