1/[u^2.(u-2)] ≡ A/u + B/u^2 +C/(u-2)=>1 ≡ Au(u-2) + B(u-2) +Cu^2u=0, => B =-1/2u=2, =>C =1/4coef. of u^2A+C=0A=-1/41/[u^2.(u-2)] ≡ (-1/4)[1/u] -(1/2)[1/u^2] +(1/4) [1/(u-2)]
