The Inverse Laplace Transform
Part 3: The Inversion Theorem
The calculations in Parts 1 and 2 have illustrated the following theorem.
Theorem. Suppose F
is a function such that
- F(z)
is differentiable for all z except for a finite numbers of poles at
z1, z2, ..., zn.
- There exist numbers M
and R such that |z F(z)| is bounded by M for all z
with |z| greater than R.
For nonnegative t, define
Then F is the Laplace
transform of f.
- For the function F1
defined by
use the theorem to find the inverse Laplace transform f. Use your
computer algebra system's inverse Laplace transform routine to check the
calculation.
- Repeat step 1 for the function F2 defined by
- Repeat step 1 for the function F3 defined by