Re: [HM] One of Euler formulas
Robert Stein (bstein@csusb.edu)
Fri, 16 Apr 1999 11:00:40 -0700 (PDT)
You really don't need much of a magnifying glass, at least based on
Cajori's article on the history of logarithms from 1914. There he explains
what Cotes was doing, and how, out of that comes the logarithm of Euler's
formula, namely
ix=log(cosx+isinx).
Bob Stein
>
> To my knowledge, the beautiful Euler's formula
>
> e^(sqr(-1) x) = cos x + sqr(-1) sen x
>
> was NOT known before Euler (but, yes, others might disagree, especially
> if they read p. 28 of Roger Cotes's _Harmonia mensurarum_ with a Whiggish
> magnifying glass!).
>
> Julio Gonzalez Cabillon