The people behind the ideas

Mathematicians

Portraits come from Wikimedia Commons and are credited on each page. Where no likeness survives, we show the person’s mathematics instead of inventing a face.

From India

Srinivasa Ramanujan1887–1920

$$\frac{\pi}{4} = 1 - \frac13 + \cdots$$

Madhava’s series for π, c. 1400

Madhava of Sangamagramac. 1340–c. 1425Aryabhata476–550 CE

$$(a^2+b^2)(c^2+d^2)$$

Brahmagupta’s identity, 628 CE

Brahmaguptac. 598–c. 668

$$x^2 - 61y^2 = 1$$

Smallest solution: x = 1766319049, y = 226153980

Bhaskara II1114–1185

$$1, 2, 3, 5, 8$$

Rhythms of 1, 2, 3, … beats

Pingalac. 3rd–2nd century BCEBaudhayanac. 800–600 BCE

$$6174$$

Kaprekar’s constant

D. R. Kaprekar1905–1986P. C. Mahalanobis1893–1972Shakuntala Devi1929–2013Harish-Chandra1923–1983Satyendra Nath Bose1894–1974C. R. Rao1920–2023

From everywhere

Leonhard Euler1707–1783Carl Friedrich Gauss1777–1855Pierre de Fermat1601–1665Euclidfl. c. 300 BCEHypatiac. 360s–415 CEEmmy Noether1882–1935Sophie Germain1776–1831Ada Lovelace1815–1852Blaise Pascal1623–1662Isaac Newton1643–1727Gottfried Wilhelm Leibniz1646–1716Alan Turing1912–1954Paul Erdős1913–1996Maryam Mirzakhani1977–2017Lewis Carroll1832–1898George Boole1815–1864al-Khwarizmic. 780–c. 850Nicole Oresmec. 1320–1382G. H. Hardy1877–1947Sofia Kovalevskaya1850–1891Kurt Gödel1906–1978Georg Cantor1845–1918Bernhard Riemann1826–1866Archimedesc. 287–212 BCEFibonaccic. 1170–c. 1250Thales of Miletusc. 626–c. 545 BCEKatherine Johnson1918–2020Mary Somerville1780–1872Évariste Galois1811–1832David Hilbert1862–1943Henri Poincaré1854–1912Pythagorasc. 570–c. 495 BCE