Find the inverse Laplace transform f(t) of F(s) = 2/(s + 5)² with a table of transform pairs, and evaluate f(0.4).
Laplace transforms worksheet with answers
1.Easy
F(s) = 2/(s + 5)²t = 0.4 s
f(0.4) =
2.Easy
Find the inverse Laplace transform f(t) of F(s) = 8s/(s² + 36) with a table of transform pairs, and evaluate f(1.2).
F(s) = 8s/(s² + 36)t = 1.2 s
f(1.2) =
3.Medium
F(s) = 23/(s² + 12s + 35). Its inverse transform has the form f(t) = A·e−5t + B·e−7t. Find the coefficient A by partial fractions.
F(s) = 23/(s² + 12s + 35)
A =
4.Medium
Find f(t) for F(s) = (s + 5)/(s² + 2s + 1) and evaluate f(0.8).
F(s) = (s + 5)/(s² + 2s + 1)t = 0.8 s
f(0.8) =
5.Hard
Solve y″ + 9y′ + 18y = 0 with y(0) = 9 and y′(0) = −11 using the Laplace transform, and find y(0.3).
y″ + 9y′ + 18y = 0y(0) = 9y′(0) = −11t = 0.3 s
y(0.3) =
6.Hard
A system obeys y″ + 11y′ + 30y = 90·u(t), with y(0) = 2 and y′(0) = 0. At t = 0 a step input u(t) = 10 is applied. Use the Laplace transform to find y(0.2).
y″ + 11y′ + 30y = 90·u(t)y(0) = 2y′(0) = 0u(t) = 10t = 0.2 s
y(0.2) =
Answer key
- 1. f(0.4) = 0.1083
- 2. f(1.2) = 4.867
- 3. A = 11.5
- 4. f(0.8) = 1.887
- 5. y(0.3) = 4.946
- 6. y(0.2) = 10.36
Full step-by-step solutions: practise this topic on examproblems.com.