Laplace Transform solution for 2nd order differential equation

In summary, the conversation was about solving a system of equations for unknown values using Cramer's rule. The person seeking help had made some errors in their calculations, but with guidance, they were able to correct their mistakes and find the correct solution. They expressed gratitude for the assistance provided by the expert.
  • #1
khnbaba
5
0

Homework Statement



d^2x/dt^2 - 3 dx/dt + 2x= 2e^3t

give that at t=0, x=5, and dx/dt=7

Homework Equations


i can't figure out how to derive the values of A, B, and C from the attempted equation solution. please help me out here. thanks


The Attempt at a Solution


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  • #2
You've got three simultaneous equations in three unknowns, A, B, and C.

You can use elimination, Cramer's rule, guessing, whatever to solve for A, B, and C.

You've done good work up to this point. I'm surprised this point has stumped you.
 
  • #3
thanks a lot steamKing you are being a big help, i went through cramer's rule examples and i think its going to solve my problem, i am going to try it now. plus i will learn some thing new :). i really appreciate your help. once again thanks
 
  • #4
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SteamKing can you have a look to the final answer. thanks
 
  • #5
For the second and third equations in your original system, for some reason you have the coefficients of A and C switched around.

Check your arithmetic in calculating the coefficients from the steps above that point, specifically where you let s = 0. Is the product of two negative numbers another negative number?
 
  • #6
are you talking about equation 2, and eq 3 in the beginning?
and s=0 was just a supposition and the arithmetic below isn't part of the question which i realize now the product of two negative numbers should be positive not negative.
 
  • #7
khnbaba said:
are you talking about equation 2, and eq 3 in the beginning?
and s=0 was just a supposition and the arithmetic below isn't part of the question which i realize now the product of two negative numbers should be positive not negative.

Yes. It appeared from your work that the calculations where s = 0 is where you started to calculate the coefficients of A, B, and C.
 
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Likes 1 person
  • #8
thanks a lot for your time and efforts.
 

1. What is a Laplace Transform solution for a 2nd order differential equation?

A Laplace Transform solution is a mathematical technique used to solve 2nd order differential equations by transforming the equations from the time domain to the frequency domain. This allows for easier manipulation and solution of complex differential equations.

2. How is the Laplace Transform solution different from other methods of solving 2nd order differential equations?

The Laplace Transform solution is different from other methods as it involves transforming the equation from the time domain to the frequency domain, instead of directly solving in the time domain. This can often simplify the equations and make them easier to solve.

3. What are the benefits of using a Laplace Transform solution for 2nd order differential equations?

One of the main benefits of using a Laplace Transform solution is that it can be used to solve complex differential equations that may not be easily solvable using other methods. It also allows for the use of initial conditions and can provide a general solution for a range of different initial conditions.

4. Are there any limitations to using a Laplace Transform solution for 2nd order differential equations?

While the Laplace Transform solution can be very useful for solving differential equations, it does have some limitations. It may not be suitable for all types of differential equations and can be more complex to use than other methods for simpler equations.

5. How can the Laplace Transform solution be applied in real-world situations?

The Laplace Transform solution can be applied in various real-world situations, such as in electrical engineering for analyzing circuits, in physics for solving problems involving oscillations and waves, and in control systems for modeling and analyzing dynamic systems. It can also be applied in various other fields that involve differential equations, such as economics and biology.

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