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If L[f(t)] = 2(s + 2) , then ƒ(0+) and ƒ(∞) are given by s² + 2s + 5
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- 0, 2 respectively
- 2, 0 respectively
- 0, 1 respectively
- 2/5, 0 respectively
Correct Option: B
= | = 2 | ![]() | ![]() | ||||
(s² + 2s + 5) | (s² + 1)² + 5 | (s + 1)² + 4 |
This is standard Laplace Transform for the function
L| exp (– at) cos ωt | = | ||
(s + a)² + ω² |
where a = 1, ω = 2
Hence ƒ(t) = 2e– t cos 2t
ƒ(0) = ƒ(0+) = 2e– 0 cos 2 × 0 = 2
ƒ(∞) = 2e– ∞ t = 0