Then I am stuck. I think the provided answer contains an error. But even if they are right, why does this last step equal f(x,y) + g(y) ???

  • dysprosium@lemmy.dbzer0.comOP
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    13 days ago

    Thx. Any idea where I can learn the right way that is clearer than this sloppy business? I basically threw in the towel of all courses since this hiccup

    • blind3rdeye@lemm.ee
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      13 days ago

      Sorry, I’m not much help with that kind of advice. My knowledge about it mostly comes from dim memories of my time at university many years ago - with only some very minor bits being kept fresh by regular use.

      My only suggestion is that it would be good to use a reputable textbook, so that you can be fairly confident that it is correct and not cutting corners; and then when you practice yourself, you should also make a conscious effort to not cut corners. (It’s always tempting to just fudge any changes to arbitrary constants as being unimportant - since they are still arbitrary constants anyway; and mostly it doesn’t matter. But that’s a bad habit, because sometimes it does matter, and won’t notice those times unless you’ve been paying attention all the time.) I won’t try to recommend specific sources though, because I’m very out-of-date with that. I’ll just say that published books used by universities are likely to be better than the notes of a private tutor or small online course.