In a complex formula or equation, it can be useful to emphasize a specific part. We can achieve this, for example, through highlighting by color or by framing. This is especially useful in presentations, where we could change the highlighted area from frame to frame while explaining.
We will take the challenge to work on more than simple basic math. So we can verify that the method works in arbitrary situations. So our original material will be the
amsmath matrices. We will illustrate a matrix transposition by highlighting submatrices and drawing arrows.
We will use TikZ for this. Such a big graphics package may seem to be a bit heavy for such a purpose at first. But it provides us with consistent styles ...