no historical likeness exists
1526 – 1572Italy
Rafael Bombelli
A number we cannot see, that nonetheless gives real answers.
A short story
An Italian engineer who spent years draining marshes: practical work, far from a university. In his spare time he wrote an algebra book in which he did something brave: he kept calculating with the square root of even though nobody knew what such a number could mean. His sums came out right and described real situations, and that opened the door to a whole new kind of number.
In their own words
I have found another kind of cube root very different from the others: it appears, but is not.
Paraphrased: adapted from Bombelli, L'Algebra, 1572, on cube roots of negative numbers.
The lab their idea turned into
Complex Lab
Step off the real number line. Meet .
Open Complex Lab →