To understand complex numbers we must first establish what real numbers are. The real number system
contains all integers and all rational numbers, where rational numbers are all fractions r/s where r and s
are integers and s NOT EQUALS 0.
The complex number system has the following properties:
1 The complex number system contains all real numbers.
2 The complex number system contains a number (usually denoted by i) such that i 2 = -1.
3 Every complex number can be written in the standard form a + bi, where a and b are real numbers and
i 2 = -1.
The number i and multiples of i (such as bi) are typically referred to as imaginary numbers. Thus, the
sum of a real number a and an imaginary number bi (a + bi) is known as a complex number.