integration constant question


by wumple
Tags: constant, integration
wumple
wumple is offline
#1
Mar13-12, 12:04 PM
P: 60
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]

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mathwonk
mathwonk is offline
#2
Mar13-12, 12:20 PM
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P: 9,422
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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