# Mathematician:Johann Bernoulli

## Mathematician

Swiss mathematician best known for his work on development of the calculus.

Taught Guillaume de l'Hôpital, who then went ahead and published his lecture notes without crediting him.

Pioneered the technique of Integration by Parts.

Younger brother of Jacob Bernoulli, with whom he did not always see eye to eye.

He and Jacob, having encountered Leibniz's early papers in his Acta Eruditorum, became his most important students.

Started his career by studying medicine, but after receiving his M.A. in medicine, he realised his mistake and turned to mathematics.

Also studied physics, chemistry and astronomy.

Contributed extensively to the field of optics.

Wrote on the theory of tides and the mathematical theory of ship sails.

Enunciated the Principle of Virtual Displacements in the field of mechanics.

Posed the Brachistochrone Problem: to find the curve down which a particle will take the shortest possible time between two points. This was solved by Jacob Bernoulli.

As a consequence of this work, often considered the originator of the calculus of variations.

Father of Nicolaus II Bernoulli, Daniel Bernoulli and Johann II Bernoulli.

Swiss

## History

• Born: 27 July 1667, Basel, Switzerland
• 1695: Appointed Professor of Mathematics at Groningen in Holland
• 1705: Succeeded Jacob Bernoulli as Professor of Mathematics at Basel
• Died: 1 Jan 1748, Basel, Switzerland

## Publications

• 1739: Hydraulica

## Also known as

Johann Bernoulli is also known as Jean or John.

Some sources report him as Johann I in order to distinguish him from Johann II Bernoulli.

## Notable Quotes

With justice we admire Huygens because he first discovered that a heavy particle falls down a cycloid in the same time no matter from what point on the cycloid it begins its motion. But you will be petrified with astonishment when I say that precisely this cycloid, the tautochrone of Huygens, is our required brachistochrone.