Leonhard Euler

By Katerina Kechris

Euler was one the leading mathematicians of the 18th century. Although the majority of his work was in pure mathematics, he contributed to other disciplines, such as astronomy and physics, as well. In his lifetime he published more than 500 books and papers, and another 400 were published posthumously.

Euler was born in Basel, Switzerland on April 15, 1707. Although his father, a pastor, was a gifted amateur mathematician he wanted his son to succeed him in the village church. Despite his love for mathematics, Euler entered the University of Basel to study theology. As a student, he attracted the attention of the Swiss mathematician, Johann Bernoulli. Bernoulli was able to convince the elder Euler to allow his son to drop his theological training and instead study mathematics. Soon after receiving his degree he was invited by the Empress of Russia in 1727 to be a professor of physics, and later mathematics, at the Academy of Sciences in St. Petersburg. He left for Berlin in 1741 and became professor of mathematics at the Berlin Academy of Sciences. He later returned to St. Petersburg at the urging of Catherine the Great in 1766. He lived there until he suffered a stroke and died in 1767. In his early 20's Euler lost his vision in one eye due to an illness. Later in life he lost the other eye, but despite this he was quite productive in his field until his death.

Euler's contributions to mathematics cover a wide range, including analysis and the theory of numbers. He also investigated many topics in geometry. For example, he worked on the mathematics behind the Greek concept of 'Perfect Bodies'. The Greeks defined the perfect body as the form built from identical regular polyhedra. There are only five such polyhedra, the tetrahedron, cube, octahedron, dodecahedron and icosahedron. These concepts were forgotten until the Renaissance, when Pacioli and Leonardo da Vinci studied them. Kepler even tried to relate the perfect bodies to the orbits of the planets. Euler was able to relate the number of faces (F), vertices (V) and edges (E) of a polyhedron by the following equation,

F + V = E + 2

from which one can derive that there are only five regular polyhdera.

__Bibliography__

- Boyer, Carl B. "A History of Mathematics." John Wiley & Sons, USA, 1991.
- Hollingdale, Stuart. "Makers of Mathematics." Penguin Books, England, 1989.
- Roberts, A. Wayne. "Faces of Mathematics" Third Edition. Harper Collins College Publishers, USA, 1995.
- Microsoft Encarta '95.