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Vector - points in same direction

  1. Oct 23, 2008 #1
    I don't know how to make the vector arrow on top of the letter so I just underlined the vectors. Also I don't know how to make the square root symbol so I just type sqrt for it.

    1. The problem statement, all variables and given/known data
    Which points in the same direction as V = (-sqrt2, sqrt3, sqrt5)
    a) 1/10 V
    b) sqrt10/10 V
    c) sqrt10 V
    d) sqrt 10 V

    2. Relevant equations

    3. The attempt at a solution
    I am not sure where to start other than calulating the sqrt of 2,3, and 5. My best guess would be c but I need to know why if that is correct or some help figuring it out.
    Please help,
  2. jcsd
  3. Oct 23, 2008 #2


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    Science Advisor
    Homework Helper

    Welcome to PF!

    Hi Marion! Welcome to PF! :smile:

    (have a square-root: √ :smile:)

    On this forum, type vectors in bold. :wink:
    (c and d look the same :confused:)

    As you probably know, on this forum we don't tell you the answer, we just try to nudge you in the right direction. :wink:

    What tests do you know for two vectors to be pointing in the same direction? :smile:
  4. Nov 3, 2008 #3
    It is a good idea to make carefull use of parentheses so that there is no
    ambiguity as to the meaning of an expression.

    Consider that for positive constants k, and vectors v, k v is in the same direction of v.
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