Pathological function: Volterra's function. This function V is differentiable but V' is not integrable! It seems like this is a counterexample to the Fundamental Theorem of Calculus, but it isn't. In calc textbooks, the FTC requires the function to be continuous, which V' isn't. pic.twitter.com/oyCTNDi1pA

— Dave Richeson (@divbyzero) November 20, 2020