Find the inverse Laplace transform f(t) of F(s) = 2/(s + 3) − 6/s with a table of transform pairs, and evaluate f(0.3).
Laplace transforms worksheet with answers
1.Easy
F(s) = 2/(s + 3) − 6/st = 0.3 s
f(0.3) =
2.Easy
A signal f(t) has the Laplace transform F(s) = (8s + 19)/(s² + 5s + 20). Find the initial slope f′(0⁺) with the initial value theorem.
F(s) = (8s + 19)/(s² + 5s + 20)
f′(0⁺) =
3.Medium
Find f(t) for F(s) = (5s + 9)/(s² + 2s + 1) and evaluate f(0.4).
F(s) = (5s + 9)/(s² + 2s + 1)t = 0.4 s
f(0.4) =
4.Medium
Find f(t) for F(s) = (s + 38)/(s² + 4s + 4) and evaluate f(0.3).
F(s) = (s + 38)/(s² + 4s + 4)t = 0.3 s
f(0.3) =
5.Hard
A system is described by the differential equation y″ + 2y′ + 5y = 2u′ + 14u, with input u(t) and output y(t). Find its transfer function G(s) = Y(s)/U(s) (zero initial conditions) and evaluate the impulse response g(t) at t = 0.75 s. Find g(0.75).
y″ + 2y′ + 5y = 2u′ + 14ut = 0.75 s
g(0.75) =
6.Hard
Solve y″ + 5y′ + 6y = 0 with y(0) = 6 and y′(0) = −4 using the Laplace transform, and find y(0.2).
y″ + 5y′ + 6y = 0y(0) = 6y′(0) = −4t = 0.2 s
y(0.2) =
Answer key
- 1. f(0.3) = −5.187
- 2. f′(0⁺) = −21
- 3. f(0.4) = 4.424
- 4. f(0.3) = 6.476
- 5. g(0.75) = 2.894
- 6. y(0.2) = 4.994
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