Interactive Mathematics
Interactive Mathematics: Complex Numbers: Basic Definitions
After reviewing the process of solving quadratic and cubic equations, a definition of an imaginary number is given. Also included is a demonstration of simplifying powers of the imaginary number and writing complex numbers. Examples are...
CK-12 Foundation
Ck 12: 1.5 From Quadratics to Complex Numbers
This section introduces imaginary and complex numbers in the context of solutions to quadratic equations that don't have real-number solutions.
Illustrative Mathematics
Illustrative Mathematics: N Cn, a Rei Complex Square Roots
Working with complex numbers allows us to solve equations that cannot be solved with real numbers. Here we will investigate complex numbers which arise as square roots of certain complex numbers. Aligns with N-CN.A.2 and A-REI.A.1.