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Math Help - 3d

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    3d

    pliz help me to plot the three dimensions accurately by using the graph show it step by step,eg.(-5,4,4)
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  2. #2
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    Quote Originally Posted by zasi View Post
    pliz help me to plot the three dimensions accurately by using the graph show it step by step,eg.(-5,4,4)
    Hello,

    I'm not quite certain what you don't understand.

    First you need a coordinate-system. You have given a point in 3-D-space. So I assume that you should use a coordinate-system with 3 axes. For convenience I assume the these axes are perpendicular to each other.

    Now you have to determine how you want to draw these axes:

    i)Put the y- and the z-axis into the drawing plane. Then the x-axis has to be reduced bei a constant faktor. 1/2*√(2) ≈ 0.707 is not a bad choice. Then you can construct a cuboid(?) with the origin and your given point at opposite sides auf a diagonal. (see attachment)

    ii)Only the z-axis is in the drawing plane. All axes are scaled equal. Then you have an isometric coordinate-system in which you can very easily construct the cuboid to locate the given point. (see attachment)

    EB
    Attached Thumbnails Attached Thumbnails 3d-zasi_isometric1.gif   3d-cosy_rechtwinklg.jpg  
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  3. #3
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    Hello, zasi!

    pliz help me to plot the three dimensions accurately
    by using the graph. Show it step by step: e.g. P(-5,4,4)

    If you've never done this before, you need to know some basics.

    We take our familiar xy-plane and "lay it on the floor".
    Then the z-axis will run up and down.

    The first "octant" (where all three coordinates are positive) looks like this:
    Code:
                z
                |
                |
                |
                |
                |
                |
                * - - - - - - - y
               /
              /
             /
            /
           /
          x

    It may help the visualization if I draw in the "walls" and "floor".
    Code:
                z
                * - - - - - - *
               /|             |
              / |             |
             /  |             |
            /   |             |
           *    |             |
           |    * - - - - - - * y
           |   /             /
           |  /             /
           | /             /
           |/             /
           *- - - - - - -*
          x

    I remind you that the z-axis extends below the "floor"
    . . (that is where z is negative)
    that the y-axis extends to the left of the "left wall",
    and the x-axis extends behind the "back wall".


    To plot P(-5, 4, 4), note what it says:
    . . x = -5, y = 4, z = 4.

    Starting at the origin, we move -5 in the x-direction
    . . (that's 5 units behind the "back wall"),
    then move +4 in the y-direction
    . . (that's 4 units to the right),
    then move +4 in the z-direction
    . . (that's 4 units up).
    And there is point P(-5, 4, 4).

    It's difficult to draw (or type) a three-dimensional situation
    . . on a two-dimensional screen, but I'll try.
    Code:
                z           P
                |           o
                |           :
                |           :4
                |           :
                |   * - - - *
                |  /    4
                | /-5
                |/
                * - - - - - - - y
               /
              /
             /
            /
           /
          x

    Think of directions to your friend's new apartment.

    You start at a mutually-agreed location, say, City Hall.

    You are told to drive 5 blocks north,
    . . then and 4 blocks east, locating the building,
    . . then take the elevator to the fourth floor.
    And there is his/her apartment.

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