On a graph, this man's namesake path visits each edge exactly once, and the
On a graph, this man's namesake path visits each edge exactly once, and the line connecting the orthocenter and circumcenter of a triangle is also named for him. He lends his name to a method of solving differential equations by estimating the slopes, and he also proved that there is no solution to the Seven Bridges of Konigsberg problem. For 10 points, identify this mathematician who gives his name to the base of the natural logarithm, a number symbolized by the letter "e."
On a graph, this man's namesake path visits each edge exactly once, and the line connecting the orthocenter and circumcenter of a triangle is also named for him.
Leonhard {Euler}