What are imaginary numbers in maths? I know how to use them, but what do they actually represent?
Imaginary numbers are those you fill in on your annual tax return.
Let me give you two answers that address two things that you would do well understanding.
1) Rooster is a moderator on this site---he helps run things and frequently gives the best links available to help someone who asks a question.
2) I don't have a mathematical keyboard. And I charge to tutor.
But, there are a few examples of the use of imaginary numbers at this link that may help you:
http://mathforum.org/library/drmath/sets/select/dm_imaginary.html
