A signal f(t) has the Laplace transform F(s) = (2s + 5)/(s² + 8s + 14). Find the initial slope f′(0⁺) with the initial value theorem.
Laplace transforms worksheet with answers
A signal f(t) has the Laplace transform F(s) = 40/(s(s² + 5s + 3)). Use the final value theorem to find the value f(∞) that f(t) settles to.
Find f(t) for F(s) = (s + 36)/(s² + 6s + 9) and evaluate f(0.4).
F(s) = (3s + 2)/(s² + 7s + 6). Its inverse transform has the form f(t) = A·e−t + B·e−6t. Find the coefficient A by partial fractions.
A system obeys y″ + 8y′ + 12y = 72·u(t). It starts at rest (y(0) = 0, y′(0) = 0) and the input is a step u(t) = 2 for t ≥ 0. Use the Laplace transform to find the output y(0.2).
A system is described by the differential equation y″ + 2y′ + 10y = u′ + 18u, 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 = 0.1 s. Find g(0.1).
Answer key
- 1. f′(0⁺) = −11
- 2. f(∞) = 13.33
- 3. f(0.4) = 4.277
- 4. A = −0.2
- 5. y(0.2) = 1.741
- 6. g(0.1) = 2.38
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