Differential equations: impulse function

In summary, taking the Laplace transform of a function involving the Dirac delta function and a sine function can be simplified by using the definition of the Laplace transform and the properties of the Dirac delta function. The Laplace transform of the given function \delta(t-1)sin(t) can be easily found by integrating with the delta function and using the definition of the Laplace transform. This does not require convolution and can be simplified further.
  • #1
seang
184
0
How do you go about taking the Laplace transform of something like...

[tex] \delta (t-1)sin(t) [/tex]

What does this even mean?
 
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  • #2
This is straight-forward, it comes directly from applying the defintions of the laplace transform and the impulse function (also called the Dirac delta "function"). So the first thing you should do is look up these definitions.
 
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  • #3
So do I have to convolve them? I know the laplace transform of both of the functions, but in order to find the laplace transform of {h(t)x(t)} it seems I'll need convolution.

And I'll have to use the fact that

[tex] \int \delta(t-t_0)f(t)dt = f(t_0) [/tex]

Am I on the right track?
 
  • #4
No, this problem, at least as you stated it, has nothing to do with convolution: you are given a function, [itex]\delta(t-1)sin(t)[/itex] and are asked to find the Laplace transform. The Laplace transform of that is
[tex]\int_0^\infty \delta(t-1)sin(t)e^{-st}dt[/tex].
That's particularly easy to integrate with that delta function in there! Do you know enough about the delta function to know why that is easy?
 
  • #5
I don't think so. It seems like the integral I posted above would help me in some way, but I'm not sure how.

EDIT: unless, is the laplace transform

[tex]e^{-s(1)}sin(1)[/tex]

?
 
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1. What is an impulse function in differential equations?

An impulse function, also known as the Dirac delta function, is a mathematical function that is zero everywhere except at one point, where it is infinite. It is often used to model sudden or instantaneous phenomena in differential equations.

2. How is an impulse function represented in equations?

In differential equations, an impulse function is represented by the symbol Δ(t) or δ(t), where t represents time. It is typically used in combination with other functions to model the behavior of a system.

3. What is the significance of an impulse function in differential equations?

The impulse function is significant in differential equations because it allows us to model and analyze systems that experience sudden changes or impulses. It allows for a more accurate representation of real-world phenomena and helps in solving complex differential equations.

4. Can an impulse function be graphed?

No, an impulse function cannot be graphed because it is infinite at one point and zero everywhere else. However, it can be represented graphically as a spike or a spike with an area under it, depending on how it is used in the equation.

5. How is an impulse function used to solve differential equations?

An impulse function is often used in combination with other functions to solve differential equations. It helps to model the behavior of a system at a specific point in time and can be used to determine the response of the system to an impulse or sudden change.

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