###### Definition1.1.7Complex Number

A complex number is a number that can be expressed in the form \(a + bi\text{,}\) where \(a\) and \(b\) are real numbers and \(i\) is the imaginary unit. In this expression, \(a\) is the real part and \(b\) (not \(bi\)) is the imaginary part. You can read more at en.wikipedia.org/wiki/Complex_number.