Which vectors define the complex number plane?

1 Answer
Jul 21, 2017

1 = (1, 0)1=(1,0) and i = (0, 1)i=(0,1)

Explanation:

The complex number plane is usually considered as a two dimensional vector space over the reals. The two coordinates represent the real and imaginary parts of the complex numbers.

As such, the standard orthonormal basis consists of the number 11 and ii, 11 being the real unit and ii the imaginary unit.

We can consider these as vectors (1, 0)(1,0) and (0, 1)(0,1) in RR^2.

In fact, if you start from a knowledge of the real numbers RR and want to describe the complex numbers CC, then you can define them in terms of pairs of real numbers with arithmetic operations:

(a, b) + (c, d) = (a+c, b+d)" " (this is just addition of vectors)

(a, b) * (c, d) = (ac-bd, ad+bc)

The mapping a -> (a, 0) embeds the real numbers in the complex numbers, allowing us to consider real numbers as just complex numbers with a zero imaginary part.

Note that:

(a, 0) * (c, d) = (ac, ad)

which is effectively scalar multiplication.