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I hate linear algebra!

  1. Oct 9, 2013 #1
    There, that feels better...
  2. jcsd
  3. Oct 9, 2013 #2
  4. Oct 10, 2013 #3
    It's dry at first, but when you see how it starts to tie all the other math together you've learned - differential equations, orthogonal polynomials, Fourier series, and obviously the stuff you do in QM which you may not have realized with linear algebra the whole time... it's actually a pretty cool subject.

    Matrices, however, will always be dry to me I think - unless I'm programming them.
  5. Oct 10, 2013 #4


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    Just curious: did you like Geometry?
  6. Oct 10, 2013 #5


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    IMHO, you can never know too much linear algebra!
  7. Oct 10, 2013 #6
    From what I have seen there is no doubt about it's usefulness, its the not being able to see what I'm doing that is frustrating :P

    I picked up several supplementary texts but they all seem to emphasize proofs of the procedures as opposed to why and how they work. Even Anton's book on the subject was dry, yikes!

    I love it, favorite subject by far although it seems to be a bit of a lost art today with so much emphasis towards Calculus for geometric derivations (at least for the engineering program at my school). I love what calculus can do but I prefer the old school :)
  8. Oct 10, 2013 #7


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    Linear algebra can be viewed as the theory of vectors (and vector spaces), and their linear transformations ... which are the matrices when you have chosen an explicit basis.

    Much of the rest is the mechanics of how to do this, and the conditions that apply.

    There are many important applications, from the Schroedinger equation (H |psi> = E |psi>), which is an eigenvalue equation, etc.
  9. Oct 10, 2013 #8
    what about non-linear algebra =)
  10. Oct 10, 2013 #9
    I am already convinced of linear algebras usefulness, the problem I am having is we are just learning the basics and no one seems to be able to show how these things work. If on an elementary level it is difficult to 'see' then I fear what is to come.

    On the subject of vectors, no doubt trigonometry combined Descartes wonderful coordinates is a powerful combination of techniques by bringing in coordinates to trigonometry. I am routinely amazed at it's usefulness and the insight it provides as this is a whole new way of doing trig for me.

    Going just outside the realm of the textbook (Calc III) we can see how vectors can be used for solving certain types of second degree multivariable polynomials, WoW! This is one subject area I will be dedicating much time to during winter break!

    It is a shame there isn't more time for exploration during the semester. In the meantime I hold out hope there will be a reasonable tie in with linear algebra at some point...
  11. Oct 10, 2013 #10
    There seems to be a love hate thing with this subject, and I have a feeling it has a lot to do with the teacher. It's actually a very beautiful subject. The way some of the proofs and identities and things work out - it's very nice and neat. Not messy like calculus. Nice and..well, linear. I don't know how else to say it. don't give up!
  12. Oct 10, 2013 #11

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    And the student. It takes a certain kind of person who can appreciate abstract mathematics as a thing of beauty. Other people want, or even need, to see that abstract mathematics be made concrete (see how it is applied) before they can begin understanding it. Those other people probably shouldn't be math majors.

    The same goes with the sciences and engineering. I know I've seen posts here by mathematicians who just don't quite grok science. They understand the math with no problem, but the how and why they should use this math or that is a struggle. They found a much better fit to the way they think over in math world.
  13. Oct 10, 2013 #12
    Yes, true. I ultimately found that i had a love for abstraction, and that applied mathematics was tedious and messy. All those natural forces of the universe kept getting in the way of my pretty equations. so I became a math major.

    However, I know a lot of math majors (and at least one teacher who has a masters) who are abstraction-oriented but for some reason still do not like linear algebra. Maybe it's still too 'practical' for them?

    -Dave K
  14. Oct 10, 2013 #13
    I have no idea if this is similar to what you are looking for, but it definitely a "pictograph" of least squares regression to "see" what the math is doing.

    Linky to the page

  15. Oct 10, 2013 #14
    Hmmm. Is linear regression part of linear algebra? Actually it is discussed in the applications section of a textbook of mine. But it also discusses applications of LA to differential equations.
    Last edited: Oct 10, 2013
  16. Oct 10, 2013 #15

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    It depends. Least squares regression? Absolutely. That least squares is linear is what makes it so easy. On the other hand, a lot of robust estimation techniques are not linear. Many aren't even differentiable (e.g., minimax techniques). Robust estimation is not easy. To make it somewhat tractable, most (all?) robust estimation techniques make locally linear approximations -- and then rinse and repeat.
  17. Oct 10, 2013 #16
    I was unaware that abstract math immediately equated to techniques that very few people understand. These processes did not just 'appear' on a sheet of paper, they were made by people who developed them. In this class (and the books I have seen so far) it seems the emphasis is primarily on the technique while the way how these ideas came to fruition are forgotten.

    I am a firm believer in that we shouldn't use something unless we understand it. For me this applies to all mathematics, even the basics like being able to derive Pi, e, the quadratic, identities, etc. etc. (and not through memorization but by actual reasoning). If the way of mathematicians today does not follow this path then I am saddened by the state of affairs for such a wonderful subject.
  18. Oct 10, 2013 #17
    So much for engineering!
  19. Oct 10, 2013 #18
    Hah! :D
  20. Oct 10, 2013 #19

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    That's a bit naive.

    You haven't told us the book, and you haven't even told us the target audience of the class. Is this
    • A linear algebra class for math majors,
    • A linear algebra course for non-math majors, or
    • An applied mathematics class that covers linear algebra along with other stuff (and just when you think you are starting to get one subject the instructor will say "and now for something completely different", switching to integral equations and Green's functions)?
  21. Oct 10, 2013 #20


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    LA is extremely dull until you get to infinite dimensional topological vector spaces. Then stuff gets interesting :) but finite dimensional LA is very boring I agree. The spaces are way too well behaved.
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