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Should I memorize all the derivations in QM?

  1. Jul 17, 2014 #1
    Hi. I'm a self-learner, and I'm doing an introductory QM from Griffiths. My question is should I memorize all the derivations and proofs in the book or I just have to memorize the final results? Another point is that I have nobody to ask about my solutions to problems or to help me in the hard ones, so, is it okay to skip the problems or should I solve them all?
  2. jcsd
  3. Jul 17, 2014 #2


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    Rather than memorize things, you'd do much better to make sure that you UNDERSTAND them, then you should be able to reproduce them if needed.
  4. Jul 17, 2014 #3

    Vanadium 50

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    It is more important to remember than to memorize.
  5. Jul 17, 2014 #4
    It's probably even more important at the undergrad level to know how to apply those derivations to other situations and the results of those derivations to solve problems.

    If you were coming from the perspective of an undergrad QM course, you would probably fail all the exams if your strategy was just 'memorize derivations'
  6. Jul 17, 2014 #5
    I guess, you should try your best, and see which problems you're able to solve. If you see you can't solve any of them, I suggest re-reading the chapter. If you can do I'd say 60-70% of the exercices, you can move on to the next chapter. But I don't know much about Griffiths Introductory, so if it really is hard, then you should just skip the problems that are way to hard, at your level of understanding.
    Isn't there anyone (a teacher, a physics student or such) who could help you out with this book ?
  7. Jul 17, 2014 #6
    Aha. I think that I understand them clearly but I just don't spend time studying them carefully -I mean the derivations-. But I think I have to spend more time on them. Thanks for help :)
  8. Jul 17, 2014 #7
    - Griffiths offers a small number of problems at the end of each section (sometimes 2 or 3 problems only) but not all of them are quite hard. And some of them are marked so that every reader should do them carefully.

    - No. I don't know anybody to help me. It is even worse to tell you that maybe there is nobody to help me in the city I live in :\
  9. Jul 17, 2014 #8
    As an undergrad QM student 2 years ago, I did QM with the Griffiths book. I argue it is far more important to be able to do the problems than memorize the derivations. My exams were never straight derivations. The problems really aren't too hard from Griffiths - some were tedious algebra, but never crazy impossibly hard. It's designed for a 3rd year undergrad.
  10. Jul 17, 2014 #9
    My problem is that I can't even check whether my answers are true or false
  11. Jul 17, 2014 #10
    You can - Griffiths QM textbook solutions are all over the internet because it's such a common undergrad book. Have you tried googling something like 'Griffiths quantum mechanics solutions PDF'?
  12. Jul 17, 2014 #11
    Is that what you're looking for ? <<link deleted>>
    Last edited by a moderator: Jul 17, 2014
  13. Jul 17, 2014 #12

    My point exactly. If you (OP) wanted to see if you were doing the problems right - all you needed was a simple google search.

    Just FYI - I think the 3rd edition is the newest for quantum. But still. It could be the 4th now.
    Last edited by a moderator: Jul 17, 2014
  14. Jul 17, 2014 #13
    By now, you can even legally find entire textbooks, so I guess you shouldn't have too much trouble finding the solutions of such a book.
  15. Jul 17, 2014 #14

    My you in the above was directed at the op, sorry ill edit that.
  16. Jul 17, 2014 #15


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    From the bottom of the second page of the PDF referenced by the deleted link:

    We do not allow posting of links to such material, unless they are explcitly authorized by the publisher.
  17. Jul 17, 2014 #16
    My bad, wasn't aware of that.
  18. Jul 17, 2014 #17
    Thanks a lot guys for your help. I will try to handle it :)
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