Albert Girard
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 ) in the Netherlands, where he studied at Leiden from 1617. Previously, he was a professional lutenist. Later, he was an engineer in the army of the Prince of Orange, as seen for example from a letter Gassendi. Girard also translated works on fortress design 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 led ( one of the first ) the use of brackets in the letter a statement to order write to longer computation instructions correctly. So did some contemporaries such as Christopher Clavius (1608 ), Richard Norwood ( 1631), but could not prevail until the end of the 17th century.