Euler

It was delightful to run across an article by John Derbyshire on Leonard Euler:

... the mathematician Leonhard Euler (1707–83), one of the great yet little-known figures from Europe’s Age of Enlightenment. Euler’s discoveries continue to influence such disparate fields as computer networking, harmonics, and statistical analysis, and they did nothing less than transform pure mathematics. Children still learn Euler’s lessons in school. It was Euler, for instance, who gave the name i to the square root of –1.

It was Euler, by the way, who popularized the symbol π in its ­now-­familiar ­usage.

He also assigned it the symbol by which it [Euler's number] has ever since been known: e

The famous Euler equation e^iπ+1=0 manages to establish a correlation among five of the most important numbers (0, 1, i, e, and ­π—­the last three all owe their symbols to Euler!) as well as among three key operations (addition, multiplication, and exponentiation).

His greatest mathematical work of this period was the 1748 masterpiece Introduction to Analysis of the Infinite. “Analysis” is a key word in modern math. It names, in fact, all of that part of math that depends on the idea of a finite result emerging from some infinite process: The limits of infinite sequences, infinite sums and products, all of calculus and the classical theory of functions—this is “analysis” as the word is now used. It was the Introduction, more than anything else, that turned the meaning of the word toward this modern sense.

And here is a bit about the author of the article:

John Derbyshire is a freelance writer, novelist, and commentator living in New York. His 2003 book Prime Obsession was awarded the Mathematical Association of America’s Euler Book Prize for “an outstanding book about mathematics.”