What are leonhard euler's inventions?

Leonhard Euler, an influential Swiss mathematician and physicist, made significant contributions across various fields, including calculus, graph theory, and number theory. He introduced important concepts such as the Euler's number (e), the Eulerian path in graph theory, and the Euler-Lagrange equation in calculus of variations. Additionally, he developed the notation for functions, the concept of a mathematical graph, and contributed to the understanding of mechanics and optics. His work laid foundational principles that continue to shape modern mathematics and physics.