## Mathematicians Of The Day

### 15th April

On this day in 1831 Gauss introduces the term "complex" for

See THIS LINK.

On this day in 2013 Google released an Euler doodle.

The postage stamp of one of today's mathematicians at THIS LINK was issued in 1938.

*a + bi*. Most of the 17th and 18th century writers spoke of*a + bi*as an imaginary quantity. Gauss saw the desirability of having different names for*ai*and*a + bi*, so he gave to the latter the Latin expression*numeros integros complexos*.See THIS LINK.

On this day in 2013 Google released an Euler doodle.

The postage stamp of one of today's mathematicians at THIS LINK was issued in 1938.

Click on Ⓟ for a poster.

##### Born:

- 1452: Leonardo da Vinci Ⓟ
- 1548: Pietro Cataldi
- 1707: Leonhard Euler Ⓟ
- 1809: Hermann Grassmann Ⓟ
- 1886: Aurel Angelescu Ⓟ
- 1921: MaurĂcio Peixoto Ⓟ
- 1923: Enrico Magenes Ⓟ
- 1928: Paul Butzer Ⓟ
- 1929: Brooke Benjamin Ⓟ
- 1932: John Lewis Ⓟ
- 1934: James Wiegold Ⓟ

##### Died:

- 1446: Filippo Brunelleschi Ⓟ
- 1704: Johann Hudde Ⓟ
- 1754: Jacopo Riccati Ⓟ
- 1878: James Booth Ⓟ
- 1934: George Moffat
- 1983: Vera Nikolaevna Faddeeva Ⓟ
- 1985: Lazar Matveevich Gluskin Ⓟ
- 1990: Karl Heinrich Weise Ⓟ
- 1997: Eugene Graham
- 1999: Floyd Burton Jones Ⓟ
- 2007: Leslie Woods Ⓟ
- 2018: George Oster Ⓟ

#### Quotation of the day

##### From Leonhard Euler

For since the fabric of the universe is most perfect and the work of a most wise creator, nothing at all takes place in the universe in which some rule of the maximum or minimum does not appear.