Find the inverse Laplace transform f(t) of F(s) = 10/(s + 3)² with a table of transform pairs, and evaluate f(0.25).
Laplace transforms worksheet with answers
1.Easy
F(s) = 10/(s + 3)²t = 0.25 s
f(0.25) =
2.Easy
A signal f(t) has the Laplace transform F(s) = 20/(s(s² + 6s + 10)). Use the final value theorem to find the value f(∞) that f(t) settles to.
F(s) = 20/(s(s² + 6s + 10))
f(∞) =
3.Medium
Find f(t) for F(s) = 55/(s(s + 5)(s + 6)) by partial fractions, and evaluate f(0.3).
F(s) = 55/(s(s + 5)(s + 6))t = 0.3 s
f(0.3) =
4.Medium
F(s) = 38/(s² + 11s + 24). Its inverse transform has the form f(t) = A·e−3t + B·e−8t. Find the coefficient A by partial fractions.
F(s) = 38/(s² + 11s + 24)
A =
5.Hard
Solve y″ + 7y′ + 12y = 0 with y(0) = 5 and y′(0) = −8 using the Laplace transform, and find y(0.3).
y″ + 7y′ + 12y = 0y(0) = 5y′(0) = −8t = 0.3 s
y(0.3) =
6.Hard
A system obeys y″ + 7y′ + 12y = 36·u(t), with y(0) = 1 and y′(0) = 0. At t = 0 a step input u(t) = 10 is applied. Use the Laplace transform to find y(0.3).
y″ + 7y′ + 12y = 36·u(t)y(0) = 1y′(0) = 0u(t) = 10t = 0.3 s
y(0.3) =
Answer key
- 1. f(0.25) = 1.181
- 2. f(∞) = 2
- 3. f(0.3) = 0.8941
- 4. A = 7.6
- 5. y(0.3) = 2.77
- 6. y(0.3) = 9.042
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