An imaginary number is a root of a negative number. ( i = the square root of negative one, and 2i is the square root of negative four, etc...)
"Imaginary" numbers have gotten themselves quite a negative reputation, but the truth is they are no more real or imaginary than other numbers. (When was the last time you got into an argument with a million?) Numbers are just the way we represent qualitative features of our universe. For example, when society progressed to the point where we needed to evaluate one person's debt to another, negative numbers were developed. People were baffled by the concept, but they did what they were supposed to do, and now they are accepted as fact. Imaginary numbers are the same, though their applications are more vague, like the motion of electricity in a circuit, or in the phases of quantum particles.
· 1 decade ago