I've also asked this in MathOverflow, but since the equation in question is related to acceleration and physical phenomenon, I figure this is also a good place.

I was asked to ID the following, but can't figure out what it's for. Laplace Transform of acceleration (x double-dot)?

Original EQ

(Sorry that I can't provide a sharper image - this is all I have access to)

I don't recognize the infinite sum, and there are some squiggles around the r in the denominator that I can't quite make out.

I tried to transcribe it, but since I'm not entirely sure what's going on in the denominator, I can't be certain it's accurate.


It seems odd to me to see a negative exponent in the denominator, and it's confusing using i as a counting variable.

Thanks in advance.


There is none. This was sent to me by a friend, off of a "what is this" site. No known artist, location, date, etc.

Edit #1

It seems that the double closed integral is from infinity to phi. But still not much help.

Edit #2 - Re-done Equation with "knowns"

Based on some comments, and things not previously seen/added to original transcribed equation, I've got the following:


The changes aren't substantial. The coefficient for the r' in the denominator has been proposed as being n, or 2. Additionally, having stared at this a bit longer, the two 2 exponents could also be sloppily-written thetas. Probably not.

All-in-all, it seems that this is most likely trolling.


closed as off-topic by sammy gerbil, Jon Custer, Kyle Kanos, ACuriousMind Jul 6 '17 at 21:07

  • This question does not appear to be about physics within the scope defined in the help center.
If this question can be reworded to fit the rules in the help center, please edit the question.

  • 3
    $\begingroup$ I'm voting to close this question as off-topic because this is not a question about physics. $\endgroup$ – sammy gerbil Jul 6 '17 at 18:56
  • $\begingroup$ Why do you think the equation relates to acceleration and a physical phenomenon? $\endgroup$ – sammy gerbil Jul 6 '17 at 18:57
  • $\begingroup$ @sammygerbil I suppose an odd usage of variables, by the original artist, could mean otherwise. That being said, I've yet to see an x double-dot that was anything other than acceleration. The dots above the x are not just to represent derivatives, but more specifically derivatives with respect to time. The second derivative of x wrt time is: acceleration. Acceleration, position, radii of curvature (i.e. r), all point to physics. $\endgroup$ – Birrel Jul 6 '17 at 19:08
  • $\begingroup$ The comment by Willie Wong in MathOverflow seems to me the best interpretation (xkcd.com/356). $\endgroup$ – sammy gerbil Jul 6 '17 at 19:47

This is non-sense (or perhaps 'art-work'). You have an integral on x and yet x appears on the LHS. Probably the artist had too much to drink...

  • $\begingroup$ Yeah, I'm not sure. I was also looking into Lagrangian, but nothing came up (maybe they write all their "L" characters like that?). Also, what you've posted is definitely a comment, and not an answer or solution. In the future, an opinion should be a direct comment to the question at hand. $\endgroup$ – Birrel Jul 6 '17 at 16:56
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    $\begingroup$ I changed 'looks like non-sense' to 'is non-sense' and it has now become an answer. I was being polite by saying it looks like non-sense. $\endgroup$ – Borun Chowdhury Jul 6 '17 at 17:02
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    $\begingroup$ x doesn't appear on the LHS. L(x'') appears on the LHS, which is not x but a function of the second derivative of x. It's perfectly normal to write something like f(x) = integral(x dx) anyway. $\endgroup$ – NeutronStar Jul 6 '17 at 17:05
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    $\begingroup$ @Joshua $x$ on the RHS is a dummy variable (in your equation and that in the photo), it disappears when the definite integral is performed. The argument of the RHS is $\phi$, not $x$. $\endgroup$ – sammy gerbil Jul 6 '17 at 19:45
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    $\begingroup$ don't drink and derive $\endgroup$ – Bob Jul 6 '17 at 20:58

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