Laplace transform using properties

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SUMMARY

The Laplace transform of the function f(t)=(t-5)e^{-17(t-5)}u(t-5) is correctly calculated as \frac{e^{-5(s+17)}}{(s+17)^{2}}. However, the user encountered a discrepancy when comparing their result with Wolfram Alpha, which provided a different answer. The confusion arises from the interpretation of the variable "s" in the exponent, which should indeed be "s+17" according to the properties of the Laplace transform.

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  • Understanding of Laplace transforms and their properties
  • Familiarity with the unit step function, u(t)
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phlstr
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Homework Statement


Find the laplace transform of
f(t)=(t-5)e^{-17(t-5)}u(t-5)

The Attempt at a Solution



The answer I got was \frac{e^{-5(s+17)}}{(s+17)^{2}}.
I thought I finally understood the process, but when I plugged it into wolfram alpha, the answer I got was different...

http://www.wolframalpha.com/input/?i=laplace+transform+of+((t-5)e^(-17(t-5)))*theta(t-5)

Shouldn't the "s" in the exponent be "s+17" or is my understanding really wrong??
 
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Wolfram Alpha's answer is the correct one.
 

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