Christoph Gudermann
= Christoph Gudermann
{wiki=Christoph_Gudermann}
Christoph Gudermann was a German mathematician, born on March 29, 1798, and died on April 21, 1852. He is best known for his work in trigonometry and for introducing the "Gudermannian" function, which relates circular and hyperbolic trigonometric functions without the need for complex numbers.