# What is tha derivative of an unit impulse function?

Discussion in 'Math' started by abdurahman saeed, Jul 21, 2010.

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1. ### abdurahman saeed Thread Starter New Member

Apr 5, 2010
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i want solution for my Q.
What is tha derivative of an unit impulse function?

2. ### tubelite New Member

Jul 20, 2010
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from what i understand the derivative only works for continuous or piece wise continuous functions. the impulse is neither and therefore doesn't have a derivative. Remember also that impulse func helps us mathematically but has no real world application. So again you could say that the derivative for the impluse func is zero for x =/=0 and not defined for x=0. I hope that helps

Jul 7, 2009
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Look up the Dirac delta function on wikipedia and it will give you what you want. The informal answer is a positive delta function immediately followed by a negative-going delta function -- i.e., pretty much the same conceptually if you differentiated a narrow, tall pulse.

Feb 12, 2010
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5. ### Papabravo Expert

Feb 24, 2006
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@abdurahman saeed -- I'm not sure it is useful to assign the delta function a specific value at the origin. The only statement you can make is that the integral from minus infinity to plus infinity is equal to 1. Thinking of it as having an infinite value there is not a particularly helpful concept. In signal processing, the ability of a time shifted delta function to pick out or sample another function is a more useful concept.

@tubelite - your response is incorrect

The derivative of a delta function is called the unit doublet.

http://en.wikipedia.org/wiki/Unit_doublet

It is zero everywhere except the origin where it has some interesting behavior. Like other functions of this type it is differentiable.

Last edited: Jul 22, 2010
6. ### tubelite New Member

Jul 20, 2010
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oh thank you very much for correcting me.

7. ### abdurahman saeed Thread Starter New Member

Apr 5, 2010
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thank you very much

8. ### Papabravo Expert

Feb 24, 2006
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Glad to help. Sorting through vast quantities if information on the web can be a daunting task. Like a good journalist ask questions and try to find corroboration for anything you find: especially on wikipedia

9. ### kongweitao New Member

Jan 3, 2010
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只听说过冲击函数（unit impulse function）在（-8，+8）的积分好像是1吧？忘记了

Apr 5, 2008
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Hello,

Bertus

Sep 6, 2010
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12. ### Ganesh karri New Member

Oct 24, 2014
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the derivative of impulse function is doublet

13. ### Papabravo Expert

Feb 24, 2006
10,021
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If that was a statement, it is redundant.
Congratulations on resurrecting a zombie thread that died 4 years ago.

Ganesh karri likes this.
14. ### Wendy Moderator

Mar 24, 2008
20,735
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Welcome to AAC.

Congratulations, you have practiced the arcane art of necromancy, the revival of a long dead thread. Likely the OP (Original Poster) has solved his problem in the years that has passed, or thrown it away, or something.