Where's my mistake? Laplace Transforms

In summary, the conversation is about finding the inverse Laplace transform and the person asking for help has made a mistake in their partial fractions decomposition. They receive assistance in correcting their mistake.
  • #1
jegues
1,097
3

Homework Statement



Find the inverse laplace transform. (see figure attached for question as well as my attempt)

Homework Equations





The Attempt at a Solution



I came up with a different answer than the given solution, and I can't figure out where I went wrong.

We are given a table of common Laplace transforms and can refer to them without proof.

I've got a feeling I made a mistake just because of how my partial fractions decomposition came out, it just doesn't make any sense.

Thanks again!

EDIT: I found my mistake in my partial fractions decomposition. A+B = 0, B = -1, C=0
 

Attachments

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  • #2
Your partial fractions are wrong. You said [itex]A=1, B=C=0[/itex], but plugging those values in, you get,
[tex]\frac{1}{s(s^2+1)} = \frac{A}{s} + \frac{Bs+C}{s^2+1} = \frac{1}{s}[/tex],

which isn't quite true.

Edit: Sorry, I didn't see your edit :).
 

Related to Where's my mistake? Laplace Transforms

1. What are Laplace Transforms and why are they used?

Laplace Transforms are mathematical tools used to solve differential equations. They transform a function of time into a function of complex frequency, making it easier to solve certain types of equations. They are commonly used in engineering and physics to model and understand systems that involve time.

2. How do I know if I made a mistake when using Laplace Transforms?

If you are using Laplace Transforms to solve a differential equation, you can check your answer by taking the inverse Laplace Transform of the solution. If the result matches the original function, then you have likely not made a mistake. Additionally, you can use online calculators or software to verify your solution.

3. What are some common mistakes when using Laplace Transforms?

Some common mistakes when using Laplace Transforms include using the wrong formula, not properly accounting for initial conditions, and incorrect algebraic manipulations. It is important to carefully follow the steps and formulas for Laplace Transforms to avoid these errors.

4. Are there any tips for using Laplace Transforms effectively?

One tip for using Laplace Transforms effectively is to practice and become familiar with the formulas and steps. Additionally, it can be helpful to break down complex functions into simpler ones before applying the Laplace Transform. Finally, always double-check your work and use online resources or textbooks for guidance if needed.

5. Can Laplace Transforms be used for any type of function?

No, Laplace Transforms can only be used for functions that are defined for all values of time t greater than or equal to 0. They also cannot be used for functions that have an infinite or discontinuous derivative at any point in time. It is important to check the validity of using Laplace Transforms for a specific function before attempting to solve a problem.

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