Rotations about an Arbitrary Axis using Quaternions

Go to 8:44 to skip the explanation. Someone commented that they were interested in rotations about an arbitrary axis. I did a quick video demonstrating how Quaternions can be employed to do this. An interesting method which can be proven using quaternions is also the Rodrigues Rotation Formula method, which I would strongly encourage looking into. Quaternions are fun, but a bit time consuming. Around 8:44 I start doing an example using Quaternions. If you look closely, you'll see a simple math error that throws off the results.