Leonhard Euler

Leonhard Euler was a Swiss polymath who made big contributions to science and math. He was born on April 15, 1707, and died on September 18, 1783. Euler worked as a mathematician, physicist, astronomer, and engineer.

Euler started the studies of graph theory and topology. He made important discoveries in many parts of math, such as analytic number theory, complex analysis, and infinitesimal calculus.

Euler is known for creating much of the math language and notation we use today. He used the Greek letter π to show the ratio of a circle’s circumference to its diameter. He was also the first to use the letter i for the imaginary unit √-1. Euler introduced the notation f(x) for functions, the Greek letter Σ for adding numbers, and Δ for small changes. His work changed how we study and use math.

Euler also helped with applied mathematics and engineering. His studies of ships made navigation better. His work on how light behaves helped create better microscopes and telescopes. Euler also made Isaac Newton’s laws of motion easier to understand for moving objects. He laid the groundwork for many areas of physics and engineering.

Euler is considered one of the most important contributors to math and science. He wrote over 866 publications. His work still influences math and science today. Even after his death, famous mathematicians like Pierre-Simon Laplace and Carl Friedrich Gauss praised Euler’s work.

Early life

Leonhard Euler was born in Basel, Switzerland, on April 15, 1707. He was the oldest of four children in a family that liked learning. Soon after he was born, his family moved to Riehen, where his father worked as a pastor.

From a young age, Euler was good at math. He started at the University of Basel when he was just 13. There, he was helped by Johann Bernoulli, a famous mathematician. Bernoulli taught Euler with hard books and meetings each week. With Bernoulli’s help, Euler decided to study math instead of becoming a pastor like his father.

Career

Leonhard Euler started his career at the Imperial Russian Academy of Sciences in Saint Petersburg. He arrived there in 1727 and worked with Daniel Bernoulli. He held several jobs, including one in the mathematics department. He later joined the Russian Navy as a medic but soon focused on mathematics.

Euler then lived in Berlin for 25 years. During this time, he wrote many important books, such as his text on functions. He also tutored a princess and wrote many letters to explain science in simple ways. In 1766, Euler returned to Saint Petersburg, where he kept working on mathematics until he passed away.

Personal life

Leonhard Euler married Katharina Gsell, the daughter of a painter, in 1734. They bought a house near the Neva River. After Katharina passed away, Euler married her half-sister, Salome Abigail Gsell. They had 13 children together, but only five lived past childhood. Euler was known for his memory and kindness, even after he lost his sight.

Euler’s eyesight got worse over time. He lost most of the vision in his right eye in 1738 and later in his left eye as well. Even with poor vision, he kept working hard and produced many mathematical papers.

Contributions to science

Main article: Contributions of Leonhard Euler to mathematics

Leonhard Euler made big contributions to many areas of mathematics and science. He worked on geometry, calculus, trigonometry, algebra, and number theory, as well as physics and astronomy. His work fills many books, and his ideas helped many fields.

Euler helped develop calculus and used it to solve problems in physics. He created new ways to write math ideas with symbols, like using "f(x)" for functions and the letter "e" for a special number. He also solved hard math problems with infinite sums and special numbers. His work linked different areas of math and science, leading to new discoveries.

Personal philosophy and religious beliefs

Euler was a strong Christian all his life. He thought the Bible was inspired by God. He wrote about his beliefs in letters and a book.

Euler did not agree with some other thinkers. He called their ideas wrong and not based on belief in God. There is a fun story about Euler using math to show a philosopher that God exists, but this story is probably not true. It was likely made up later by someone else.

Legacy

Main article: List of topics named after Leonhard Euler

Leonhard Euler is one of the greatest mathematicians of all time. Many people think he was the most productive thinker in math and science. He is often placed among the best mathematicians in history, with famous names like Carl Friedrich Gauss, Isaac Newton, and Archimedes.

Euler appeared on Swiss money and stamps, and an asteroid was named after him to honor his work in math.

Selected bibliography

Leonhard Euler wrote many important books and papers. Some of his well-known works include:

• Mechanica (1736)
• Introductio in analysin infinitorum (1748) (Introduction to Analysis of the Infinite)
• Institutiones calculi differentialis (1755) (Foundations of differential calculus)
• Vollständige Anleitung zur Algebra (1765) (Elements of Algebra)
• Institutiones calculi integralis (1768–1770) (Foundations of integral calculus)
• Letters to a German Princess (1768–1772)

Euler’s work has been carefully collected and organized. The Euler Archive began at Dartmouth College and is now hosted by the University of the Pacific. The Swiss Academy of Sciences started the Euler Commission to publish all of Euler’s works in a series called Opera Omnia. This project has published many volumes with Euler’s mathematics, science, and letters.