Edward Routh (1831–1907) is best known for the Routh-Hurwitz theorem, a theorem that gives criteria for control systems to be stable. Routh was apparently a productive man because he has quite a few things named after him. I keep running into him, and today I wrote a couple blog posts about his work.
The first is a post about Routh’s mnemonic for calculating the moment of inertia for various standard shapes. The post briefly mentions his “stretch” theorem that says you can skew shapes a certain way without changing the moment of inertia.
The second post is about Routh’s triangle theorem, an extension of Ceva’s theorem that gives an equation for the area of a triangle formed by connecting the vertices of another triangle to its sides.
Enjoy.