MacTutor
15th April
On this day in 1831 Gauss introduces the term "complex" for 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.
See THIS LINK.
On this day in 2013 Google released an Euler doodle.