Step by step
The question
Question: find the Laplace transform of t.
ℒ{t} =
1 The idea
The Laplace transform turns a function of t into a function of s.
It is an integral, but we almost never work it out: we use a table made from it.
ℒ{f(t)} = ∫ from 0 to ∞ of e^(−st) f(t) dt
The table rows we need.
tn → n!sn + 1
2 Use the table
Each part by its row: t gives 1/s².
ℒ{t} = 1s2
3 Check
Let's check: read the table backwards.
1/s² comes from t: the question.
Right!
backwards: 1s2 → t
Let's look back.
First: the idea.
Then: use the table.
Last: check.
Answer
ℒ{t} = 1s2