How Does the Step Function Relate to the Derivative of the Dirac Delta Function?

CasualDays
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Derivative Using Dirac Delta Function

Homework Statement


Let \theta(x) be the step function:

\theta(x) be equivalent to

1, if x > 0
0, if x \leq 0

Show that \frac{d \theta }{dx} = \delta(x)


Homework Equations


In the previous portion I was able to prove
x \frac{d}{dx} (\delta(x))= -\delta(x)


The Attempt at a Solution


I thought the problem was a heavyside problem but upon closer inspection, I noticed that on the heavyside step function it is 1 when x \geq 0.

So how do I resolve this? Is there a way to change it so that it looks like a heavyside function, because that makes the problem much more convenient.:smile:
 
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Hi CasualDays! :smile:

(have a theta: θ and a delta: δ :smile:)

Hint: what is 1 - θ(x)? :wink:
 
tiny-tim said:
Hi CasualDays! :smile:

(have a theta: θ and a delta: δ :smile:)

Hint: what is 1 - θ(x)? :wink:


It's always the easy solutions that allude me..:biggrin:
 
To solve this, I first used the units to work out that a= m* a/m, i.e. t=z/λ. This would allow you to determine the time duration within an interval section by section and then add this to the previous ones to obtain the age of the respective layer. However, this would require a constant thickness per year for each interval. However, since this is most likely not the case, my next consideration was that the age must be the integral of a 1/λ(z) function, which I cannot model.
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