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

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The discussion centers on the relationship between the step function θ(x) and the Dirac delta function δ(x). It establishes that the derivative of the step function, defined as 1 for x > 0 and 0 for x ≤ 0, is equal to δ(x). Participants explore the connection to the Heaviside step function, noting that the Heaviside function is 1 for x ≥ 0, which complicates the comparison. A hint is provided to consider the expression 1 - θ(x) to facilitate understanding. The conversation emphasizes the importance of recognizing the nuances in defining these functions for proper mathematical analysis.
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:
 

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