he was mentored by g. h. hardy in the early 1910s. after getting his degree at cambridge, ramanujan did his own work. he compiled over 3500 identities and equations in his life. some of the identities were found in his “lost notebook”. when the notebook was discovered, mathematicians proved almost all of ramanujan's work. his discoveries have led to many advancements in mathematics. his formulae are now being used in crystallography and string theory.