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Top 10 Fascinating Facts about Leonhard Euler

Born on 15 April 1707 in Basel, Switzerland, Leonhard Euler is considered to be one of the greatest mathematicians in history. Apart from being a mathematician, Euler was also a physicist, astronomer, geographer, logician, and engineer. 

He founded the studies of graph theory and topology and made pioneering and influential discoveries in many other branches of mathematics such as analytic number theory, complex analysis, and infinitesimal calculus.

Euler spent most of his adult life in Saint Petersburg, Russia, and in Berlin, then the capital of Prussia.  He died on 18 September 1783, but his works remain the best reference for the different fields of mathematics

Here are the top 10 fascinating facts about him.

1. He Received his early education from his Father

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Leonhard Euler was the oldest of four children, two younger sisters, and a younger brother. His family moved from Basel to the town of Riehen, Switzerland, where he spent most of his childhood.

From a young age, Euler received schooling in mathematics from his father, who had taken courses from Jacob Bernoulli some years earlier at the University of Basel.

Euler was sent to live at his maternal grandmother’s house when he was around eight years old.  He enrolled in the Latin school in Basel. He also received private tutoring from a young theologian with a keen interest in mathematics.

2. Euler Earned his Master鈥檚 Degree at the Age of 16

Euler enrolled at the University of Basel at the age of 13. He received the course on elementary mathematics under the supervision of a family friend Johann Bernoulli.

It was during this time that his father allowed him to become a mathematician rather than a pastor. He received private lessons and mathematics books to study from Bernoulli that improved his mathematics grasp.

In 1723, at the age of 16 years, Euler received a Master of Philosophy with a dissertation that compared the philosophies of Ren茅 Descartes and Isaac Newton.

3. He Lost his Eyesight

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Euler’s eyesight deteriorated as his life progressed and at the age of 31 years, he became almost blind in his right eye. He blamed the cartography he performed for the St. Petersburg Academy for his condition.

In 1766 a cataract in his left eye was discovered, and a few weeks later a failed surgical restoration rendered him almost totally blind. Despite his condition, he continued to produce an average of one mathematical paper per week.

4. He applied Mathematics even in Music

A notable funny aspect of Euler’s life was his attempt to apply mathematics to everything. One unusual interest was the application of mathematical ideas in music.

In 1739 he wrote a New Theory of Music hoping to incorporate musical theory as part of mathematics. It did not attract much attention as it was too mathematical for musicians and too musical for mathematicians.

5. He Presented the Graph Theory

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In 1735, Euler presented a solution to the problem known as the Seven Bridges of K枚nigsberg. The city of K枚nigsberg, Prussia was set on the Pregel River and included two large islands that were connected to each other and the mainland by seven bridges.

Euler discovered the formula {\displaystyle V-E+F=2} relating the number of vertices, edges, and faces of a convex polyhedron, and hence of a planar graph. The constant in this formula is now known as the Euler characteristic for the graph and is related to the genus of the object.

6. Leonhard Euler Popularized the use of 蟺

 The symbol 蟺 or pi was first introduced in 1706 by William Jones. It became popular when Leonhard Euler decided to utilize it in 1737.

He regularly used it when referring to the ratio of circumference to diameter in a circle. His documentation of this mathematical analysis helped in standardizing pi.

7. Two Important math Numbers are Named after Leonhard Euler

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Students who love Mathematics will undoubtedly remember his name. The 鈥�e鈥� and the 鈥�纬鈥� in the equations are known as 鈥淓uler鈥檚 Number鈥� and 鈥淓uler Constant,鈥� respectively. An interesting fact about Leonhard Euler is that no other mathematician, past or present, has the distinct honor of having two numbers named after them.

8. Euler Introduced the Mathematical Notation

Euler introduced and popularized several notational conventions through his numerous and widely circulated textbooks. Most notably, he introduced the concept of a function and was the first to write f(x) to denote the function f applied to the argument x.

He also introduced the modern notation for the trigonometric functions, the letter e for the base of the natural logarithm (now also known as Euler’s number), the Greek letter 危 for summations, and the letter i to denote the imaginary unit. 

The use of the Greek letter 蟺 to denote the ratio of a circle’s circumference to its diameter was also popularized by Euler, although it originated with Welsh mathematician William Jones.

9. He Died of a Brain Haemorrhage

In St. Petersburg on 18 September 1783, after lunch with his family, Euler was discussing the newly discovered planet Uranus and its orbit with Lexell when he collapsed and died from a brain hemorrhage.

Euler was buried next to Katharina at the Smolensk Lutheran Cemetery on Vasilievsky Island. In 1837, the Russian Academy of Sciences installed a new monument, replacing his overgrown grave plaque. To commemorate the 250th anniversary of Euler’s birth in 1957, his tomb was moved to the Lazarevskoe Cemetery at the Alexander Nevsky Monastery.

10. He was Married Twice

On 7 January 1734, he married Katharina Gsell daughter of Georg Gsell, a painter from the Academy Gymnasium in Saint Petersburg. The young couple bought had 5thirteen children of which only five survived.

After his wife’s death in 1773, Euler married her half-sister, Salome Abigail Gsell, and Their marriage lasted until his death in 1783.