Nikolai Lobachevsky, Russian mathematician and geometer (died 1856)

Nikolai Lobachevsky

Russian mathematician (1792–1856)

Nikolai Ivanovich Lobachevsky was a Russian mathematician and geometer, known primarily for his work on hyperbolic geometry, otherwise known as Lobachevskian geometry, and also for his fundamental study on Dirichlet integrals, known as the Lobachevsky integral formula.