Inverse Laplace Transform

Formula: $E = mc^2$

Problem

Find the inverse Laplace transform of:

\[F(s) = \frac{3s - 4}{s^2 - 3s + 2}\]

Solution

Step 1: Factor the denominator

\[F(s) = \frac{3s - 4}{s^2 - 3s + 2} = \frac{3s - 4}{(s - 1)(s - 2)}\]

Step 2: Partial fraction decomposition

\[F(s) = \frac{A}{s - 1} + \frac{B}{s - 2}\]

Solving for A and B:

\[F(s) = \frac{1}{s - 1} + \frac{2}{s - 2}\]

Step 3: Apply inverse Laplace transform

\[f(t) = \mathcal{L}^{-1}\{F(s)\}\]
\[f(t) = \mathcal{L}^{-1}\left\{\frac{1}{s - 1} + \frac{2}{s - 2}\right\}\]
\[f(t) = \mathcal{L}^{-1}\left\{\frac{1}{s - 1}\right\} + 2\mathcal{L}^{-1}\left\{\frac{1}{s - 2}\right\}\]

Step 4: Use table of inverse transforms

Function Laplace Transform
\(e^{at}\) \(\frac{1}{s-a}\)
\[f(t) = e^t + 2e^{2t}\]


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