## Leonhard Euler

## Leonhard Euler

Elif Demir

Leonhard Euler (15.04.1707, Switzerland) is a Swiss mathematician who is known as one of the inventors of pure mathematics since he is the founder of the calculus of variations, geometry, mechanics, and number theory. He demonstrated the application of mathematics in physics and technology. He worked on the trigonometric functions and center of gravity on a triangle. He is the mathematician who is known for the Euler line passing through the intersection point of heights from different sides of a triangle. He represented the values of trigonometric functions as a parameter of geometric lines’ length. In his prior work “Introduction to Analysis of Infinity,” he defined the “Infinity.” He is a pioneer in the Terminology of Mathematics. He proved one of the

most crucial theorems on logarithms as his initial is recognized as the base of all-natural logarithms. Euler’s Identity Equation is the combination of complex numbers and trigonometry. Euler’s Identity states that = cos θ + i sin θ), with complex numbers (e.g., ). He proved the imaginary algorithms of negative numbers and declared that each complex number has infinitely many algorithms. He also worked on ways to create magic squares. Meanwhile, he came up with another type of squares that could be a template for producing magic squares and named them “Latin squares,” in which every number or symbol appears once and only once in each row and column. His first publication has served as the foundation of calculus since he wrote the primary formulas of differentiation and numerous methods of indefinite integration. He worked on Euler’s Three-Body Problem as a tutor of three Russian mathematicians; however, even after working on it for fifteen years, this problem is still not solved. He discovered the reciprocal of a quadratic function, and this law of quadratic reciprocity, as part of the number theory, is awarded twelve times by the Paris Academy Prize, and now there is a prize named after him.

References:

Bellos, Alex. “Magic Squares Are given a Whole New Dimension.” The Guardian, Guardian News and Media, 3 Apr. 2011, https://www.theguardian.com/science/2011/apr/03/magic-squares-geomagic-lee-sallows.

Boyer, Carl B.. "Leonhard Euler". Encyclopedia Britannica, 14 Sep. 2021, https://www.britannica.com/biography/Leonhard-Euler. Accessed 17 October 2021.

"Euler, Leonhard ." Complete Dictionary of Scientific Biography. . Encyclopedia.com. 22 Sep. 2021 <https://www.encyclopedia.com>.

Grinstein, Louise; Lipsey, Sally I. (2001). "Euler, Leonhard (1707–1783)". Encyclopedia of Mathematics Education. Routledge. p. 235. ISBN 978-0-415-76368-4.

Davis, Philip J. (1959). "Leonhard Euler's integral: A historical profile of the gamma function". The American Mathematical Monthly. 66: 849–869. doi:10.2307/2309786. JSTOR 2309786. MR 0106810.