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What is this equation called?

  1. Jun 20, 2013 #1
    Hello everybody, What is this equation called? I'm from non-English speaking country and I need to look up materials about how to solve it, Thank you.
    1ake7HP.png
     
  2. jcsd
  3. Jun 20, 2013 #2

    tiny-tim

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    Welcome to PF!

    Hello Goethe10! Welcome to PF! :smile:
    (why have you written a "d" there? :confused:)

    This is an ordinary equation,

    and the four possible answers are dervatives of it,

    except that instead of writing dy/dx = f(x), they've written them dy = f(x)dx :wink:
     
  4. Jun 20, 2013 #3
    Haha, sorry.
    It was just smudge done by paint tool, not an actual D, sorry about confusion :P
    What do you mean "ordinary equation" Can you please give me the full name? Thanks.
     
  5. Jun 20, 2013 #4

    tiny-tim

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    i mean it's just an equation, there's nothing special about, there's nothing to look up! :smile:

    (just differentiate it!!)
     
  6. Jun 20, 2013 #5
    Ah, I see! :D Thank you
    So
    3+2x^3 would be
    6x^2
    Can you please tell me what does "dy" means?
     
  7. Jun 20, 2013 #6

    tiny-tim

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    correct! :smile:
    if you'd written the equations in full, you would have written:

    y = 3+2x3

    So dy/dx = 6x2

    The "dy" and "dx" in "dy = 6x2dx" are called differentials (or infinitesimal differentials).

    You can always rewrite any dy/dx equation so that the dy and dx are on opposite sides …

    look that up in almost any book on calculus :wink:
     
  8. Jun 21, 2013 #7
    Thank you! :)
     
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