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Really dumb question: why do we use e_i for unit vectors?

  1. Mar 28, 2008 #1
    Anybody know the history of why something like [tex]\mathbf{e}_i[/tex] is conventionally used for unit vectors (as opposed to u for Unit which is less common).

    I assume this originates from another language? If so I'm curious what language and what word.
     
  2. jcsd
  3. Mar 28, 2008 #2

    D H

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    German, I suspect - ein.
     
  4. Mar 28, 2008 #3
    Ah. One (unit). Thanks!
     
  5. Mar 28, 2008 #4
    I'd always been told it was short for "element."
     
  6. Mar 28, 2008 #5

    HallsofIvy

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    Never believe what a math teacher tells you!
     
  7. Mar 28, 2008 #6
    I agree, "e" for "Einheitsvektor" meaning unit vector.

    Might also be derived from Euclidean though..who knows for sure..:smile:
     
  8. Mar 28, 2008 #7
    How come?
     
  9. Mar 28, 2008 #8

    D H

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    He's a math teacher trying to revive Epimenides paradox. Follow his advice: Don't believe anything he says.
     
  10. Mar 28, 2008 #9
    I am assuming he is implying with this, that we, students, must check everything out on our own, no matter who tells us that sth is true or not. We have to verify everything on our own, right, is this what halls is saying, right?

    Ok, i am gonna check the meaning of that paradox on wiki.
     
    Last edited: Mar 28, 2008
  11. Mar 30, 2008 #10
    whats Epimenides paradox??
     
  12. Mar 30, 2008 #11
    google it!!!
     
  13. Mar 30, 2008 #12
    aaahhh i know that from the "SAT" exam

    the lier paradox

    those logic questions took a decade from my life
     
    Last edited: Mar 30, 2008
  14. Mar 31, 2008 #13
    I actually found this discussion to be fairly informative. I never think that asking for historical reasons for notation is a stupid question.
     
  15. Mar 31, 2008 #14
    I should have labelled the post "non-technical question: ..." ;)
     
  16. Apr 2, 2008 #15

    mathwonk

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    why does this nonsense thread receive space? mindless relief?
     
  17. Apr 5, 2008 #16
    Would there be something wrong with that?
     
  18. Apr 5, 2008 #17

    HallsofIvy

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    Epimedes' paradox was to say that "All Cretan's are liars". Of course, Epimedes was himself a Cretan. There is, in fact, a place in the Bible (New Testament. I've forgotten exactly where but may be in Paul's epistle to the Corinthians) in which we are warned to beware of Cretans- "they say of themselves that they are liars"!
     
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