Tschirnhaus' cubic curve is sometimes called this man's eponymous cubic.  
Tschirnhaus' cubic curve is sometimes called this man's eponymous cubic.  He was one of the five original solvers of the brachistochrone problem, yet his solution wasn't published for nearly 300 years.  He famously acknowledged Leibniz and both Jacob and his teacher Johann Bernoulli in his text, the first ever on differential calculus.  FTP, name this French mathematician whose eponymous rule is used to find limits of indeterminate forms.
Tschirnhaus' cubic curve is sometimes called this man's eponymous cubic.  
Guillaume de L'Hopital or L'Hospital [lo-PEE-tal]