Imaginary Numbers Are Real [Part 2: A Little History]

Want to learn more or teach this series? Check out the Imaginary Numbers are Real Workbook: www.welchlabs.c....
Imaginary numbers are not some wild invention, they are the deep and natural result of extending our number system. Imaginary numbers are all about the discovery of numbers existing not in one dimension along the number line, but in full two dimensional space. Accepting this not only gives us more rich and complete mathematics, but also unlocks a ridiculous amount of very real, very tangible problems in science and engineering.
Part 1: Introduction
Part 2: A Little History
Part 3: Cardan's Problem
Part 4: Bombelli's Solution
Part 5: Numbers are Two Dimensional
Part 6: The Complex Plane
Part 7: Complex Multiplication
Part 8: Math Wizardry
Part 9: Closure
Part 10: Complex Functions
Part 11: Wandering in Four Dimensions
Part 12: Riemann's Solution
Part 13: Riemann Surfaces
Part 2 especially owes a debt to Paul Nahin's excellent book: An Imaginary Tale: The Story of sqrt(-1). Nahin presents a very thorough account of the development of imaginary numbers, which was invaluable in creating this series.