Mathematician:Albert Girard

Mathematician
Professional French lutenist who also studied mathematics, working in the fields of algebra, trigonometry and arithmetic.

Gave an inductive formula for the Fibonacci numbers.

First stated in 1632 that every prime of the form $4 k + 1$ is the sum of two squares in only one way. Invented the symbol $\sqrt[n]x$ for the $n$th root of $x$.

His work led eventually to the creation of group theory.

Nationality
French

History

 * Born: 1595 in St Mihiel, France.
 * Died: 8 Dec 1632 in Leiden, Netherlands.

Theorems

 * Girard's Theorem

Books and Papers

 * 1625: A French translation of the works of


 * 1625: A French translation of Books $\text V$ and $\text {VI}$ of 's (the  edition)

(titles unknown)
 * 1626: A treatise on trigonometry


 * 1629: Invention Nouvelle en l'Algèbre