Bernoulli, Jakob (1654–1705)

Swiss mathematician who with his brother Johann pioneered German mathematician Gottfried Leibniz's calculus. Jakob used calculus to study the forms of many curves arising in practical situations, and studied mathematical probability; Bernoulli numbers are named after him.

Jakob Bernoulli's papers on transcendental curves (1696) and isoperimetry (1700, 1701) contain the first principles of the calculus of variations. It is probable that these papers owed something to collaboration with Johann. His other great achievement was his treatise on probability, Ars Conjectandi (1713), which contained both the Bernoulli numbers (a series of complex fractions) and the Bernoulli theorem.

Jakob Bernoulli was born in Basel. On a trip to England in 1676 he met Irish physicist Robert Boyle and other leading scientists, and decided to devote himself to science. He became particularly interested in comets (which he explained by an erroneous theory in 1681) and in 1682 began to lecture in mechanics and natural philosophy at the University of Basel. During the next few years he came to know the work of Leibniz and began a correspondence with him. In 1687 he was made professor of mathematics at Basel.