complex number
complex quantity
imaginary number
imaginary

The square of an imaginary number is a negative real number.

Both imaginary numbers have equal claim to being the number whose square is 1.

That is to say, for the purposes of the calculation one must measure time using imaginary numbers, rather than real ones.

How can one show that imaginary numbers really do exist?

The second part of a complex number is an imaginary number.

All the other imaginary numbers are multiplied by a real number.

The difference of two imaginary numbers is found similarly.

He was the one who finally managed to address the problem with imaginary numbers.

In complex form it is written as an imaginary number:

For example, there can exist elements that have square -1, as with imaginary numbers.