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Vector Notation Inconsistencies

  1. Jan 18, 2012 #1
    My teacher writes 3 dimensions like this:

    3spaceaa-1.png


    My textbook writes it like this:

    3spacea.png



    If my online H/W is not directly written by my teacher and not directly written by my textbook (MasteringPhysics online HW), then when presented with a vector such as:

    A = (2,1,-4)

    Should I read it as:

    A = (2x, 1y, -4z) or A = (2z, 1x, -4y)


    I'm going to guess the H/W is more in line with the teacher's convention than my textbook's convention and that's how i'm going to proceed. However, if anyone has more insightful input as to how to read this vector, i'm all ears.
     
  2. jcsd
  3. Jan 18, 2012 #2
    x= 2, y=1, z= -4

    The coordinate system is a matter preference both is correct but a point is identified as (x,y,z)
     
  4. Jan 18, 2012 #3
    both ARE correct, poor grammer
     
  5. Jan 18, 2012 #4
    RTW, I appreciate your response, thanks.

    P.S.

    "is" ..."are...it's all the same to me. ..Good thing this good place is not called "Grammerforums" :)
     
  6. Jan 18, 2012 #5

    cepheid

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    Gold Member

    The two coordinate systems are the same. Both are "right-handed." They're just viewed from different orientations. Take the first one and rotate it 90 degrees counterclockwise around the x-axis. Then rotate it 90 degrees around the y-axis. The result is what is shown in the second diagram.

    To actually *change* the coordinate system, (e.g. to make it "left-handed"), you'd have to change which direction is positive for one of the axes.

    Now, to actually answer your question: when vectors are written down in terms of a comma-separated list of their Cartesian components in parentheses, the ordering is always (x,y,z). To do anything else would be very unusual and probably lead to confusion.
     
  7. Jan 18, 2012 #6

    I actually had to pick up the nearest box shaped item in my vicinity and rotate it to prove it to myself lol.

    I appreciate your feedback, thanks.
     
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