Find the inverse Laplace transform f(t) of F(s) = 20/(s² + 9) with a table of transform pairs, and evaluate f(1.2).
Laplace transforms worksheet with answers
A signal f(t) has the Laplace transform F(s) = (−3s² + 30s + 50)/(s(s + 2)(s + 3)). Use the initial value theorem to find f(0⁺), the value of f(t) just after t = 0.
Find f(t) for F(s) = 15/(s² + 4s + 29) by completing the square, and evaluate f(0.75).
Find f(t) for F(s) = (5s + 9)/(s² + 4s + 4) and evaluate f(0.8).
A system is described by the differential equation y″ + 6y′ + 8y = 3u′ + 5u, 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 = 0.2 s. Find g(0.2).
A system is described by the differential equation y″ + 2y′ + 5y = 3u′ + 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).
Answer key
- 1. f(1.2) = −2.95
- 2. f(0⁺) = −3
- 3. f(0.75) = −0.3826
- 4. f(0.8) = 0.848
- 5. g(0.2) = 1.237
- 6. g(0.75) = 2.692
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