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Thread: ratios, derivatives, and scale

  1. #1 ratios, derivatives, and scale 
    Forum Ph.D.
    Join Date
    Dec 2006
    Location
    Norway
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    i wonder why these things are called different things when they are basically the same written in 3 different ways.
    look at this:

    map scale: 1:1000 or 1cm on the map equals 1000cm in reality.
    ratio : 1/1000 when the first number increase with 1, the second number increases with 1000.
    derivative:
    dx 1
    = ____
    dy 1000

    if dx increases with 1, dy increases by 1000.

    these basically do the same thing!
    why do we have to learn the same thing 3 times?

    wouldn't it be better to simply call it ratio instead of map scale and derivative as well?


    when you have eliminated the impossible, whatever remains, however improbable, must be the truth
    A.C Doyle
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  3. #2  
    Forum Professor river_rat's Avatar
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    Jun 2006
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    South Africa
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    That is because they are not doing the same thing - for starters derivatives are local!!!


    As is often the case with technical subjects we are presented with an unfortunate choice: an explanation that is accurate but incomprehensible, or comprehensible but wrong.
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