ABSTRACT
A complex number z is an ordered pair (x; y) of real numbers x and y. The rst number, x, is called the real part of z, and the second component, y, is called the imaginary part of z.
Addition and multiplication of two complex numbers z1 = (x1; y1) and z2 = (x2; y2) are dened by
z1 + z2 = (x1 + x2; y1 + y2); z1 z2 = (x1y1 x2y2; x1y2 + x2y1):
The complex number (0; 1) is denoted by i and is called the imaginary unit.
