Help with Laplace Transform of (t+2)sinh2t

In summary, the Laplace transform of (t+2)sinh2t is 4/(s^2 - 4) + 4s/(s^2 + 4) ^2. This can be found by using the standard rule for the Laplace transform of sinh2t, as well as the multiplication by t^n rule. The Laplace transform can also be applied to the equation by multiplying it by exp(-at) and then adding the results together. The final result can be found by integrating the equation using integration by parts.
  • #1
cabellos
77
1
My understanding of the laplace trasnform isn't so great so i would appreciate some help with this question please:

find the laplace transform of (t+2)sinh2t

now i know the laplace transform of sinh2t is 2/(s^2 -4) as this is a standard rule...

looking through textbooks they show the multiplication by t^n rule is needed and i found that the laplace transform of t (sin kt) = 2ks/(s^2 + k^2) ^2

how do i apply this to my equation... :confused:
 
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  • #2
Do not double post!
 
  • #3
the Laplace transform of (t+2) is [tex] 1/s^{2}+2/s [/tex]

If you multiply f(t) by exp(-at) then there's a shift so F(s+a) and

[tex] 2sinh(ax)=e^{xa}+e^{-ax} [/tex]

then next is just hand-work...
 
  • #4
thanks for the tips,

can u find the LT of 2sinh2t and the tsinh2t and add them together which gives 4/(s^2 - 4) + 4s/(s^2 + 4) ^2

is this correct?
 
  • #5
Yes. The definition of the Laplace tranform is:
[tex]L(f(t))= \int_0^\infty f(s)e^{-st}dt[/tex]
Since
[tex]\int (f(x)+ g(x))dx= \int f(x)dx+ \int g(x)dx[/tex]
It follows that you can add Laplace transforms.

It should be easy to integrate
[tex]\int_0^\infty (t+2)sinh t dt[/tex]
(Break it into two integrals and use integration by parts)
as an exercise.
 

Related to Help with Laplace Transform of (t+2)sinh2t

What is the Laplace Transform?

The Laplace Transform is a mathematical tool used to convert a function of a real variable, typically time, into a function of a complex variable, typically frequency. It is commonly used in engineering and physics to solve differential equations and analyze systems.

What is the formula for the Laplace Transform?

The formula for the Laplace Transform is given by L{f(t)} = ∫ e-stf(t)dt, where L{f(t)} represents the transformed function, s is a complex variable, e is the base of the natural logarithm, and f(t) is the original function.

How do you find the Laplace Transform of (t+2)sinh2t?

To find the Laplace Transform of (t+2)sinh2t, you can use the properties of the Laplace Transform and the table of Laplace Transforms to simplify the expression. First, use the linearity property to break up the function into (t)sinh2t and 2sinh2t. Then, use the time-shifting property to convert (t)sinh2t into sinh2(t-1). Finally, use the table of Laplace Transforms to find the transforms of sinh2(t-1) and 2sinh2t. Add the two transformed functions together to get the final answer.

What are the common applications of the Laplace Transform?

The Laplace Transform has many applications in engineering and physics. It is commonly used to solve differential equations, analyze linear systems, and study the stability of control systems. It is also used in signal processing, circuit analysis, and in the study of electric and magnetic fields.

What are the advantages of using the Laplace Transform?

The Laplace Transform has several advantages over other mathematical techniques. It is a powerful tool for solving differential equations, as it can transform them into algebraic equations which are easier to solve. It also allows for the analysis of systems in the frequency domain, which can provide valuable insights and simplify calculations. Additionally, the Laplace Transform has many useful properties and a convenient table of transforms, making it a versatile and efficient tool for scientists and engineers.

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