Question

In 3–5 sentences,

A. Describe why purely real numbers and purely imaginary numbers are also complex numbers.

B. Describe how to identify the real part versus the imaginary part of a complex number.

C. What does the imaginary unit, i
, represent?

(3 points)

Answer 1

Complex numbers have the form a + bi with real a and b, so purely real numbers (b = 0) and purely imaginary numbers (a = 0) are just special cases of complex numbers. In a + bi the real part is a and the imaginary part is b (the imaginary part is the coefficient of i, not the term bi). The imaginary unit i is defined by i^2 = −1 (i = √−1) and can be thought of as the unit that generates the axis perpendicular to the real axis in the complex plane.