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Integration constant question

  1. Mar 13, 2012 #1
    Hi,

    I thought that if you integrate with limits, you don't include a constant, but if you don't integrate with limits (indefinite), there is a constant. But my book gives the example (all functions are single variable functions, initially of x but then changed to s for the integration):

    [tex] f' = \frac{1}{2}(\phi'+\frac{\psi}{c}) [/tex]

    Integrating:

    [tex] f(s) = \frac{1}{2}\phi(s) + \frac{1}{2c}\int_0^s\psi + A [/tex]

    What's going on here?
     
  2. jcsd
  3. Mar 13, 2012 #2

    mathwonk

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    Science Advisor
    Homework Helper

    the first statement implies the second. I.e. if all you know about f is its derivative, then you can only know f up to an additive constant.

    try to get away from memorizing mindless rules like the (flawed) ones you stated. learn what the concepts mean.
     
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