I have read Florian Cajori's book "A history of mathematical notations."

Cajori explained about several symbols for unknown. Rudolff used weird symbols.

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I could identify some symbols: "z" for zensus, "c" with a loop for cubus, "eszett ß" for sursolidum.

But, I could not understand the symbol for radix. It looks like conjunction of "2" and "e".

Could you teach me which letter was used for radix?

  • 2
    $\begingroup$ I think it's an "rx". If you look at some older German scripts for handwriting, the end of it looks very much like a lower case $x$, and the beginning is consistent with being a handwritten $r$. And of course, "rx" as an abbreviation for "radix" makes some sense. $\endgroup$ May 18, 2015 at 14:14
  • $\begingroup$ @DanielFischer Thank you for your kind comments! $\endgroup$
    – P.-S. Park
    May 18, 2015 at 15:05


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