A signal f(t) has the Laplace transform F(s) = (4s² + 7s + 47)/(s(s + 4)(s + 7)). Use the initial value theorem to find f(0⁺), the value of f(t) just after t = 0.
Laplace transforms worksheet with answers
A signal f(t) has the Laplace transform F(s) = (2s + 17)/(s² + 11s + 28). Use the initial value theorem to find f(0⁺), the value of f(t) just after t = 0.
F(s) = (4s + 34)/(s² + 4s + 3). Its inverse transform has the form f(t) = A·e−t + B·e−3t. Find the coefficient A by partial fractions.
Find f(t) for F(s) = 30/(s(s + 1)(s + 6)) by partial fractions, and evaluate f(0.8).
Solve y″ + 7y′ + 6y = 0 with y(0) = 5 and y′(0) = 3 using the Laplace transform, and find y(0.3).
A system is described by the differential equation y″ + 3y′ + 2y = 2u′ + 17u, 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 = 1 s. Find g(1).
Answer key
- 1. f(0⁺) = 4
- 2. f(0⁺) = 2
- 3. A = 15
- 4. f(0.8) = 2.312
- 5. y(0.3) = 4.625
- 6. g(1) = 3.759
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