Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Silly Math Question! Please help!

  1. Feb 28, 2012 #1
    We say that a slope can be calculated as the ratio of the perpendicular to the base , Then what does differentiation of the equation shows "dy/dx"?
     
  2. jcsd
  3. Feb 28, 2012 #2
    Re: Silly Math Question! Plzz help!

    I'm sorry, what? Can you please clarify your question?
     
  4. Feb 28, 2012 #3

    NascentOxygen

    User Avatar

    Staff: Mentor

    Re: Silly Math Question! Plzz help!

    Differential calculus involves the evaluation of that Δy / Δx but taken to its extreme.
     
  5. Feb 29, 2012 #4
    Re: Silly Math Question! Plzz help!

    I just want to know what actually differentiation is apart from its equation ? what does it mean?
     
  6. Feb 29, 2012 #5

    NascentOxygen

    User Avatar

    Staff: Mentor

    Re: Silly Math Question! Plzz help!

    Differentiation is a way of calculating the slope at any point along a curve if you know that curve's equation.
     
  7. Feb 29, 2012 #6
    Re: Silly Math Question! Plzz help!

    Ya thats what i m saying suppose y =3x^2 then on differentiation i would get (dy/dx=6x) then at point x=3 the slope would be 18. Then isn't slope also calculated as (y2-y1)/(x2-x1) then at point x = 3 isn't it should be 9 ?
     
  8. Feb 29, 2012 #7
    Re: Silly Math Question! Plzz help!

    No, because that equation gives you the slope of the line connecting two points; we don't have two points in this case, we only have one. Remember that when we construct the derivative we actually use the above slope formula to calculate the limit of the slope as the distance of two points approaches zero.
     
  9. Mar 1, 2012 #8

    NascentOxygen

    User Avatar

    Staff: Mentor

    Re: Silly Math Question! Plzz help!

    Yes. So if you take two points (x1,y1) and (x2,y2) on that curve, where x1 and x2 are very close to 3, then that quotient will be very close to 18.
     
  10. Mar 1, 2012 #9
    Re: Silly Math Question! Plzz help!

    Then what is the significance of one over the other ? I mean in which situation which one should i prefer ?
     
  11. Mar 1, 2012 #10
    Re: Silly Math Question! Plzz help!

    This has already been explained to you. The slope formula gives you the slope of the line connecting two points; the derivative gives the slope of the tangent line at each point of the function.
     
  12. Mar 1, 2012 #11

    HallsofIvy

    User Avatar
    Staff Emeritus
    Science Advisor

    Re: Silly Math Question! Plzz help!

    What appears to be puzzling you is the limit process. I recommend you go back and review "limits". It's probably in the chapter of your Calculus book just before the derivative is introduced!
     
  13. Mar 1, 2012 #12

    NascentOxygen

    User Avatar

    Staff: Mentor

    Re: Silly Math Question! Plzz help!

    Differentiation gives the exact value of the slope at any point you choose. Using the "pair of points" method gives an approximation, you are in effect approximating the curve with a straight line.
     
  14. Mar 1, 2012 #13
    Re: Silly Math Question! Plzz help!

    Thank you i was really confused at this :)
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Silly Math Question! Please help!
  1. Silly question (Replies: 7)

Loading...