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Inverse Laplace transform of 2/(s - 1)^2

Step by step, with the reason for every step · The inverse Laplace transform · Differential Equations

Step by step

The question

Question: find the inverse Laplace transform of 2/(s − 1)².

ℒ⁻¹{2(s − 1)2} =

The inverse transform goes back: which function of t has this transform?

We read the table backwards.

ℒ⁻¹: back from s to t

1 Use the table backwards

Each piece is already a row of the table.

tne^(at) → n!(s − a)n + 1

Read the table backwards, piece by piece: 2te^(t).

f(t) = 2te^(t)

2 Check

Let's check: the table forwards turns our answer back into 2/(s − 1)².

Right!

forwards: 2te^(t) → 2(s − 1)2

Let's look back.

First: use the table backwards.

Last: check.

Answer
f(t) = 2te^(t)

Your turn

Try this one yourself, then check:

ℒ⁻¹{7(s − 1)2}
Show the answer
f(t) = 7te^(t)

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