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468 points scapbi | 3 comments | | HN request time: 0s | source
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andrewla ◴[] No.45106778[source]
It's crazy that Linear Algebra is one of the deepest and most interesting areas of mathematics, with applications in almost every field of mathematics itself plus having practical applications in almost every quantitative field that uses math.

But it is SOOO boring to learn the basic mechanics. There's almost no way to sugar coat it either; you have to learn the basics of vectors and scalars and dot products and matrices and Gaussian elimination, all the while bored out of your skull, until you have the tools to really start to approach the interesting areas.

Even the "why does matrix multiplication look that way" is incredibly deep but practically impossible to motivate from other considerations. You just start with "well that's the way it is" and grind away until one day when you're looking at a chain of linear transformations you realize that everything clicks.

This "little book" seems to take a fairly standard approach, defining all the boring stuff and leading to Gaussian elimination. The other approach I've seen is to try to lead into it by talking about multi-linear functions and then deriving the notion of bases and matrices at the end. Or trying to start from an application like rotation or Markov chains.

It's funny because it's just a pedagogical nightmare to get students to care about any of this until one day two years later it all just makes sense.

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1. dapper_bison17 ◴[] No.45107321[source]
> This "little book" seems to take a fairly standard approach, defining all the boring stuff and leading to Gaussian elimination. The other approach I've seen is to try to lead into it by talking about multi-linear functions and then deriving the notion of bases and matrices at the end. Or trying to start from an application like rotation or Markov chains.

Which books or “non-standard” resources would you recommend then, that do a better job?

replies(1): >>45107466 #
2. andrewla ◴[] No.45107466[source]
I have yet to encounter an approach that is not boring. You just have to power through it. This approach seems as good as any.

Once you get to eigenvalues (in my opinion) things start to pick up in terms of seeing that linear spaces are actually interesting.

This approach sort of betrays itself when the very first section about scalars has this line:

> Vectors are often written vertically in column form, which emphasizes their role in matrix multiplication:

This is a big "what?" moment because we don't know why we should care about anything in that sentence. Just call it a convention and later on we can see its utility.

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3. _mu ◴[] No.45111060[source]
Maybe we can petition Paul Lockhart to do a book on Linear Algebra, I would definitely buy it.