Albert Girard

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Albert Girard (* 1595 in St. Mihiel , France ; † December 8, 1632 in Leiden , Netherlands ) was a French mathematician.

Girard was born in Lorraine and fled as a Protestant (member of the Reformed Church ) to the Netherlands, where he studied in Leiden from 1617. Before that he was a professional lute player. Later he was an engineer in the army of the Prince of Orange , as can be seen, for example, in a letter from Pierre Gassendi . Girard also translated works on fortress architecture from French into Flemish and vice versa.

In 1626 he published a treatise on trigonometry in which - according to some sources - the abbreviations sin, cos and tan were used for the first time.

In 1629 he (as one of the first) introduced the use of brackets in letter arithmetic so that longer arithmetic instructions could be correctly written down. This was also done by some contemporaries such as Christophorus Clavius (1608) and Richard Norwood (1631), but it was not until the end of the 17th century that it became established.

He was the first to suspect in 1608 that a polynomial of the nth degree actually has n solutions, some of which are real, some of which are complex (see the fundamental theorem of algebra ).

annotation

  1. ↑ According to other sources, the names come from Edmund Gunter (1581–1626), who in 1624 invented a mechanical device for calculating logarithms (Gunter scale). In the description he uses the abbreviations sin and tan. For cosinus Gunter chose the designation co.sinus, which John Newton (1622–1678) changed to cosinus. The abbreviation cos was first used in 1674 by Sir Jonas Moore (1617–1679).
  2. ↑ Florian Cajori A History of Mathematics , 1893, p. 158.

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personal data
SURNAME Girard, Albert
BRIEF DESCRIPTION French mathematician
DATE OF BIRTH 1595
PLACE OF BIRTH St. Mihiel , France
DATE OF DEATH December 8, 1632
Place of death Leiden , Netherlands