Thursday, February 10, 2011

Definition of Imaginary Numbers

An Imaginary Number is a number which when squared, gives a negative number as an answer. There are many numbers that will end up with a positive answer, for example, even (-1) x (-1) = 1 since the two negatives become a plus. So, to find 2 numbers that can square to an Imaginary Number, take the square root of a negative number. The sign i is for imaginary, so, for example, the square root of -9 is (+9) x i. Actually Imaginary Numbers were once thought to be impossible, and so they were called "Imaginary", this was actually to make fun of them. But then people researched them more and discovered they were actually useful and important because they filled a gap in mathematics, but the "imaginary" name has stuck. And that is also how the name "Real Numbers" came about, real is the opposite of imaginary. There are uses for Imaginary numbers, such as AC (Alternating Current) Electricity changes between positive and negative in a since wave.
If you combine two AC currents they may not match properly, and it can be very hard to figure out the new current.
But using imaginary numbers and real numbers together makes it a lot easier to do the calculations!