Mark M. answered 08/14/19
Retired college math professor. Extensive tutoring experience.
1 / [s2(s+2)] = A/s + B/s2 + C/(s+2)
Multiply through by s2(s+2):
1 = As(s+2) + B(s+2) + Cs2
0s2 + 0s + 1 = (A+C)s2 + (2A+B)s + 2B
Equating coefficients of like powers, we get:
A + C = 0
2A + B = 0
2B = 1
So, B = 1/2, A = -1/4, C = 1/4
Thus, 1 / [s2(s+2)] = (-1/4) / s + (1/2) / s2 + (1/4) / (s+2)