“Every positive number was one of Ramanujan's personal friends”—J. E. Littlewood
Srinivasa Aiyangar Ramanujan (Tamil: ஸ்ரீநிவாச ராமானுஜன்) FRS (1887–1920) was an Indian mathematician and autodidact who, with almost no formal training in pure mathematics, made extraordinary contributions to mathematical analysis, number theory, infinite series, and continued fractions. Living in India with no access to the larger mathematical community, which was centered in Europe at the time, Ramanujan developed his own mathematical research in isolation. As a result, he sometimes rediscovered known theorems in addition to producing new work. Ramanujan was said to be a natural genius by the English mathematician G. H. Hardy, in the same league as mathematicians like Euler and Gauss.
- George S. Carr, A Synopsis of Elementary Results in Pure Mathematics: Containing Propositions, Formulæ, and Methods of Analysis, with Abridged Demonstrations., London: C. F. Hodgson and Son (1880), 290 pp.
- S. L. Loney, Plane trigonometry, London: C. J. Clay and Sons (1893).
- O’Connor, John J.; Robertson, Edmund F., “Srinivasa Aiyangar Ramanujan”, MacTutor History of Mathematics archive, University of St Andrews, http://www-history.mcs.st-andrews.ac.uk/Biographies/Ramanujan.html .