integrate d/dx(x^2)


by adamg
Tags: confused, d or dxx2, integrate
adamg
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#1
Feb3-05, 04:35 PM
P: 48
if i integrate d/dx(x^2), should i include the constant of integration? thanks
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Crosson
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#2
Feb3-05, 04:50 PM
P: 1,294
If you are working on an equation, then presumably you are integrating both sides with respect to x in which case you will have a constant of Integration (arbitrarily) on either side.

The short answer is yes, in all cases.
adamg
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#3
Feb3-05, 06:07 PM
P: 48
so it doesnt matter that you know what the function was before differentiation?

Crosson
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#4
Feb4-05, 02:15 AM
P: 1,294

integrate d/dx(x^2)


I am tempted to say that it wouldn't matter, but that would lead to inconsistent results (i.e. a different answer depending on the chosen order of operations).
HallsofIvy
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#5
Feb4-05, 11:56 AM
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PF Gold
P: 38,882
What in the world do you mean? If you start with a function f(x), differentiate it, then integrate that, whether you get the original function, that function plus an unknown constant, or that function plus a specific number depends on exactly what type of "integral" you are doing:

[itex]\int f(x)dx[/itex], the indefinite integral should have an unknown constant added because it means ALL functions whose derivative is f(x) but [itex]\int_a^xf(t)dt[/itex] would not and the value will depend upon the choice of a.


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