I have no idea how to solve the problem with the inverse laplace transforms.

*Find the Inverse laplace transform of { 3/ (s + 4) }

I guessed that the answer, f(t)would be:3 cos 2t

However it doesn't make sense because according to the table,-cos kt- is equal toF(s)=> s / (s^(2) + k^(2)).

In this case,sis not squared. I am not sure aboutkbecause I think it's not squared. If it is squared then k is equal to2. That's how I got

3 cos 2t.

however if k is not squared thenkis equal to4. I am confused...

Please help