What was the notation that Feynman made up for calculus?

September 9, 2010 6:46 PM

In which book does Feynman describe the notation he made up for calculus? And what symbols did he use?

I remember reading an essay where Richard Feynman explains that when he first started teaching himself calculus in high school, he thought that calculus notation was confusing. So he made up his own notation instead and worked with that, until he realized that he could only communicate mathematically with other people by using the normal notation.

But I don't actually remember what the actual notation was, and I've been looking through my Feynman library all night unsuccessfully. Google's impenetrable; just a bunch of his later work. I'm trying to find it because I brought it up to my pre-calculus professor on Wednesday in class and two shocking things happened. 1. He hadn't heard of it. 2. He was interested.

Anybody know? Because I really should get back to my actual math homework.

posted by sunnichka to Science & Nature (10 answers total)

You might find this question interesting.
posted by fake at 6:49 PM on September 9, 2010

Best answer: I don't have the book at hand, but I'm pretty sure that it wasn't calculus, it was trig; and what he did was write a sigma, gamma, or tau (to represent sine, cosine, and tangent respectively) whose upper right extension stuck out over the argument like we do with the square root symbol. I think he neglects to mention whether the Greek letters were upper- or lowercase. I'm 90% sure this was in "Surely You're Joking...!".
posted by AkzidenzGrotesk at 6:51 PM on September 9, 2010

Response by poster: Oh, I know about that question actually; it was written by a friend of mine. Yes, I found that passage in Surely You're Joking--but it's describing something different. That passage describes how he learned a different *method* for doing integrals. The information I'm looking for is actually the notation he made up to describe calculus. Thanks for the help though, Fake!
posted by sunnichka at 6:53 PM on September 9, 2010

Response by poster: Oh, it's coming back to me, I think it was trig! He made up different symbols to denote the 'inverse sine' because sine^-1 seemed misleading. That's still actually perfectly relevant to my class though, because my professor was lecturing on inverse functions.

If it's in "Surely You're Joking," though, I'm losing my mind. I looked at every page in that damn book tonight. Can anybody else find it?
posted by sunnichka at 6:57 PM on September 9, 2010

Okay, maybe it was "What Do You Care What Other People Think?" I'm almost certain it was one of the "with Ralph Leighton" books.
posted by AkzidenzGrotesk at 6:59 PM on September 9, 2010

Response by poster: AkzidenzGrotesk, is there another 'with Ralph Leighton' book of his essays? Because "What Do You Care" is the other book I searched pretty thoroughly tonight.
posted by sunnichka at 7:00 PM on September 9, 2010

Well, this is just weird. It's been so long ago for me, and no, I can't remember another such book. Maybe we're both losing our minds.
posted by AkzidenzGrotesk at 7:03 PM on September 9, 2010

Best answer: I found it! I had been scanning the books looking for references to calculus; that's why I couldn't find anything. It's on page 23 of "Surely You're Joking, Mr. Feynman," in the 'He Fixes Radios By Thinking!' essay.

Actually, now that I think about it, I don't think I looked through that essay the first time. I thought that one was just about when he was a kid and . . . fixing radios.

Thanks for the help, AkzidenzGrotesk!
posted by sunnichka at 7:13 PM on September 9, 2010

Response by poster: Also, I'm not totally crazy. He did make up a symbol for dy/dx that looked "something like an & sign."
posted by sunnichka at 7:19 PM on September 9, 2010

Best answer: The trig/calculus notations Feynman developed when he was 14 (in 1933) are recorded in notebooks he kept, that can now be found in Box 16, Folders 2 and 3 of "The Feynman Papers" collection at the Caltech Archives. See:
http://www.oac.cdlib.org/findaid/ark:/13030/kt5n39p6k0 .
posted by codelieb at 6:02 AM on September 10, 2010 [3 favorites]