(1208 – 1261)
From Algebra to Arithmetic and down to Geometry, mathematical sciences owe a lot to this dinosaur, who ranks among the most gifted mavens. Qin’s extraordinary works on Modular Arithmetic, of which the Chinese Remainder Theorem stands out, have remained influential for more than 700 years. After the theorem was adopted in Europe, some problems whose solutions eluded even Leonhard Euler became solvable. Similarly, his explorations of Polynomials extended to quartic degree; and to quintic equations (which are algebraically unsolvable in terms of finite additions, subtractions, multiplications, divisions, and root extractions: as proven by the later works of Niels Henrik Abel and Évariste Galois). Qin Jiushao was also an accomplished astronomer, whose narratives revealed how solstice and other related astronomical data could be derived from traditional lunisolar calendars. Apart from incorporating the zero-symbol into Chinese mathematics, Qin is credited with finding sums of arithmetic series. His expertise and techniques were sterling. He even dissected the much-talked-about Ruffini-Horner method more than 500 years before Paolo Ruffini and William Horner rediscovered it in 19th century Europe. In Geometry, he independently rediscovered Heron’s formula. And in meteorology, he developed the Tianchi basin: which is an instrument used for evaluating precipitations. Although most of his publications were lost, the survivors: such as Shushu Jiuzhang (i.e. the Mathematical Treatise in Nine Sections) indicated that he researched extensively on applied mathematics, civil engineering, architecture and surveying. Qin Jiushao’s achievements are even more awesome: considering the fact that he was a career bureaucrat who regarded science and mathematics as hobbies.