Explore the introduction to imaginary numbers, their properties, and applications through interactive lessons and examples on Khan Academy.

Sal explains how we obtain complex numbers by adding real numbers and imaginary numbers.

Learn about the imaginary unit, "i", a unique number defined as the square root of -1. It's a key part of complex numbers, which are in the form a + bi. The powers of "i" cycle through a set of …

Learn the basics of imaginary numbers and their applications through engaging video lessons on Khan Academy.

Learn what the complex plane is and how it is used to represent complex numbers. The Imaginary unit, or i , is the number with the following equivalent properties:

We're asked to add the complex number 5 plus 2i to the other complex number 3 minus 7i. And as we'll see, when we're adding complex numbers, you can only add the real parts to each …

Through a guided example with 7 - 5i, this video explains how to find the conjugate of a complex number, which is simply changing the sign of the imaginary part.

Since we don't know of any real number that equals that, we can use the imaginary number i to essentially stand in for it, like Pi. (Instead of writing out 3.141593... we just write Pi and call it …

Learn about the imaginary unit i, about the imaginary numbers, and about square roots of negative numbers.

Complex numbers let you find solutions that real numbers can't, and they help you understand and model many phenomena in nature, science, and art. In this unit, you'll learn how to create, …