## 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.

*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.

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 Ⓟ

#### Quotation of the day

##### From Leonhard Euler

If a nonnegative quantity was so small that it is smaller than any given one, then it certainly could not be anything but zero. To those who ask what the infinitely small quantity in mathematics is, we answer that it is actually zero. Hence there are not so many mysteries hidden in this concept as they are usually believed to be. These supposed mysteries have rendered the calculus of the infinitely small quite suspect to many people. Those doubts that remain we shall thoroughly remove in the following pages, where we shall explain this calculus.