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Difference between a differential, dx, and the change in a variable, delta x?

  1. Mar 18, 2005 #1
    What's the difference between a differential, dx, and the change in a variable, delta x? Is dx the change in a variable with respect to a function while delta x is the change in the domain?
     
  2. jcsd
  3. Mar 18, 2005 #2
    Delta x is like what you say, the change in x... or ... Xfinal-Xinitial. When you take a derivative with respect to x (dx being the differential) you are taking the change in x (delta x) to be infinitly small.

    So on a position-time graph when you find delta x and divide it by delta t, you find the average velocity. However, if you take the derivative of the position function with respect to time (dx/dt), you still have the same units as before, but you have found the instantaneous velocity.

    I hope this helps!
     
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