Explanation : Leonhard Euler was one of the most prolific mathematicians in history, publishing over 800 papers throughout his lifetime. He revolutionized mathematics by creating much of the notation we use today, including e, i, f(x), and the summation symbol. His most famous contribution is Euler's identity, e^ (int) 1 = 0, often called the most beautiful equation in mathematics as it connects five fundamental constants. He also made groundbreaking work in calculus, number theory, graph theory