Imaginary Unit - Definition

Definition

The powers of i return cyclic values:
(repeats the pattern from blue area)
(repeats the pattern from blue area)

The imaginary number i is defined solely by the property that its square is −1:

With i defined this way, it follows directly from algebra that i and −i are both square roots of −1.

Although the construction is called "imaginary", and although the concept of an imaginary number may be intuitively more difficult to grasp than that of a real number, the construction is perfectly valid from a mathematical standpoint. Real number operations can be extended to imaginary and complex numbers by treating i as an unknown quantity while manipulating an expression, and then using the definition to replace any occurrence of i 2 with −1. Higher integral powers of i can also be replaced with −i, 1, i, or −1:

Similarly,

Read more about this topic:  Imaginary Unit

Famous quotes containing the word definition:

    I’m beginning to think that the proper definition of “Man” is “an animal that writes letters.”
    Lewis Carroll [Charles Lutwidge Dodgson] (1832–1898)

    ... we all know the wag’s definition of a philanthropist: a man whose charity increases directly as the square of the distance.
    George Eliot [Mary Ann (or Marian)

    One definition of man is “an intelligence served by organs.”
    Ralph Waldo Emerson (1803–1882)