The greatest mathematician of the eighteenth century, **Leonhard Euler** was
born in Basel, Switzerland. There, he studied under another giant of
mathematics, **Jean Bernoulli**. In 1731 Euler became a professor of physics
and mathematics at St. Petersburg Academy of Sciences. Euler was the most
prolific mathematician of all time, publishing over *800 different books and
papers*. His influence was felt in physics and astronomy as well.

He is perhaps best known for his research into mathematical analysis. Euler's work, Introductio in analysin infinitorum (1748), remained a standard textbook in the field for well over a century. For the princess of Anhalt-Dessau he wrote Lettres à une princesse d'Allemagne (1768-1772), giving a clear non-technical outline of the main physical theories of the time.

One can hardly write a mathematical equation without copying Euler.
Notations still in use today, such as `e` and π , were introduced
in Euler's writings. Leonhard Euler died in 1783, leaving behind
a legacy perhaps unmatched, and certainly unsurpassed, in the annals
of mathematics.

cos(x) +isin(x) =e^{(ix)}

demonstrates the relationship between algebra, complex analysis, and trigonometry. From this equation, it's easy to derive the identity

e^{(π i)}+ 1 = 0

which relates the fundamental constants: 0, 1, pi, e, and i in a single beautiful and elegant statement. A poll of readers conducted by The Mathematical Intelligencer magazine named Euler's Identity as the most beautiful theorem in the history of mathematics.

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