Question

\[\Large \mathcal L^{-1} \left \lbrace \frac{1}{s^3(s^2 + 1)}\right \rbrace\]

i got the partial fraction to be \[-\frac 1s + \frac{1}{s^2} + \frac{s}{s^2+1}\]

but i have no idea how to get the inverse of that last term

Answer 1

L(cos t) = ?

Answer 2

you just have to recognize it

Answer 3

...oh yeah....

Answer 4

we did the proof together yesterday, now it's time to use that lol

Answer 5

how could i forget =_= i got so used to (s-a)^2 lol

Answer 6

so it's \[-1 + t + \cos t?\]

Answer 7

yep

Answer 8

nice. thanks

Answer 9

http://www.wolframalpha.com/input/?i=laplace+transform+-1+%2B+t^2+%2B+cos+t