Exam study haha

2. Considerf(t) = e^at for t > 0, where 'a' is a constant, then

F(s) = Integral(from 0 to infinity) e^(−st)e^(at)dt

and this integral exists fors > a, so that

L(eat) = 1/ (s-a)

fors > a.

I would have said 1/ (a-s)

Why is it not so?