Matrix multiplication as composition | Essence of linear algebra, chapter 4
Multiplying two matrices represents applying one transformation after another. Many facts about matrix multiplication become much clearer once you digest this ...
========== It is my experience that proofs involving matrices can be shortened by 50% if one throws matrices out.
-- Emil Artin Hey everyone! Where we last left off, I showed what linear
transformations look like and how to represent them using matrices. This is worth a quick recap, because it's
just really important. But of course, if this feels like more than
just a recap, go back and watch the full video. Technically speaking, linear transformations
are functions, with vectors as inputs and vectors as outputs. But I showed last time how we can think about
them visually as smooshing around space in such a way the gridlines
stay parallel and evenly spaced, and so that the origin remains fixed. The key take-away was that a linear transformation is completely determined,
by where it takes the...