Fagnano_Giulio
# Giulio Carlo Fagnano dei Toschi

### Born: 6 Dec 1682
in Sinigaglia, Italy

Died: 26 Sept 1766
in Sinigaglia, Italy

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**Giulio Fagnano** suggested new methods of solving equations of degree 2,3 and 4. He improved Bombelli's work on complex numbers. Considering triangles he looked at interesting problems such as:
Given ABC find P minimising PA+PB+PC.

For a quadrilateral ABCD find P minimising AP+BP+CP+DP .

He also discovered that if X is the centre of gravity of the triangle ABC then XA+XB+XC = (AB+BC+CA)/3. In his study of the rectification of the lemniscate, Giulio Carlo Fagnano introduced ingenious analytic transformations that laid the foundation for the theory of elliptic integrals and his work was to lead to elliptic functions. He made many other major contributions.

**References (4 books/articles)**

**References elsewhere in this archive:**

Giulio Fagnano was elected to the Royal Society of London in 1723. You can see a history of the Royal Society and a list of the members among the mathematicians in our archive.

JOC/EFR December 1996