Khan Academy
Khan Academy: Graphically Add and Subtract Complex Numbers
Add or subtract complex numbers, and plot the result in the complex plane. Students receive immediate feedback and have the opportunity to try questions repeatedly, watch a video or receive hints.
Khan Academy
Khan Academy: Polar and Rectangular Forms of Complex Numbers
Given a complex number in rectangular form, write it in polar form. And given a complex number in polar form, write it in rectangular form. Students receive immediate feedback and have the opportunity to try questions repeatedly, watch a...
Khan Academy
Khan Academy: Plot Numbers on the Complex Plane
Given a complex number, plot its corresponding point on the complex plane. Students receive immediate feedback and have the opportunity to try questions repeatedly, watch a video or receive hints.
Khan Academy
Khan Academy: Complex Number Conjugates
Given a complex number, find its conjugate or plot it in the complex plane. Students receive immediate feedback and have the opportunity to try questions repeatedly, watch a video or receive hints.
Khan Academy
Khan Academy: Angle of Complex Numbers
Given a complex number of the form a+bi, find its angle. Students receive immediate feedback and have the opportunity to try questions repeatedly, watch a video or receive hints.
Khan Academy
Khan Academy: Complex Numbers From Absolute Value & Angle
Given the absolute value and the angle of a complex number, express the number in the form a+bi. Students receive immediate feedback and have the opportunity to try questions repeatedly, watch a video or receive hints.
Lawrence Hall of Science
The Math Page: Skill in Algebra: Skill in Algebra: Complex or Imaginary Numbers
Clearly and thoroughly explains complex numbers. Provides example problems and exercises for students, with solutions available.
CK-12 Foundation
Ck 12: Polar Form of a Complex Number
[Free Registration/Login may be required to access all resource tools.] Here you will learn how to convert complex numbers from rectangular form to polar form. You will also explore the graphs of complex numbers on a polar graph.
CK-12 Foundation
Ck 12: Plot Polar Coordinates
[Free Registration/Login may be required to access all resource tools.] Here you will learn how to convert and graph complex numbers in trigonometric or polar form using the polar coordinate system, which is similar in some ways to (x,...
CK-12 Foundation
Ck 12: Complex Numbers
[Free Registration/Login may be required to access all resource tools.] This lesson covers the powers of i, and adding and subtracting complex numbers, as well as how to plot them in the complex plane. Students examine guided notes,...
Interactive Mathematics
Interactive Mathematics: Products and Quotients of Complex Numbers
Complex numbers are multiplied and divided using polar and exponential forms. Several examples are provided to demonstrate the process. Includes practice questions.
Interactive Mathematics
Interactive Mathematics: Polar Form of Complex Numbers
Using vectors as a starting point, this site demonstrates how complex numbers can be written in polar form. Several examples are included that require you to write complex numbers in polar and rectangular form and also represent them...
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...
Math Open Reference
Math Open Reference: Complex Numbers
Explore complex numbers with this easy reference guide. Learn that complex numbers lie on a two-dimensional flat plane and have two components called the real and imaginary parts. Provides definitions and interactive activities that...
Khan Academy
Khan Academy: Parts of Complex Numbers
Determine the real and the imaginary parts of complex numbers.
CK-12 Foundation
Ck 12: Algebra Ii: 1.6 the Complex Plane
This section includes operations with imaginary and complex numbers and plotting numbers on the complex plane.
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.
Math Notes and Math Tests
Pre Calculus Notes: Complex Numbers [Pdf]
The resource discusses complex numbers. Topics examined are the complex plane, complex conjugates, dividing complex numbers, and complex zeros of functions.
Wolfram Research
Wolfram Math World: Real Part
This MathWorld site contains a graphical example of the real part of a complex number.
University of Toronto (Canada)
How Can One Show That Imaginary Numbers Really Do Exist?
Contains a brief summary about the theory of imaginary numbers.
Windstream
Ojk's Precalculus Study Page: Geometric Representation of Complex Numbers
An introduction to viewing the complex plane in terms of polar coordinates. Assumes knowledge of the conversion formulas. Includes several examples and pictures.
Windstream
Ojk's Precalculus Study Page: Powers of Complex Numbers
An introduction to DeMoivre's Theorem for quickly finding the powers of complex numbers. Assumes knowledge of polar form of complex numbers. Includes several examples and pictures.
Windstream
Ojk's Precalculus Study Page: Polar Coordinates Sample Test
A practice test covering the polar form of complex numbers, including using DeMoivre's Theorem to find powers and roots of complex numbers.
University of California
Ucla: Complex Plane
This site from UCLA provides great information on the complex plane. The main feature of the site is an applet that illustrates the complex plane. It is a great learning tool in dealing with the features of the complex plane.