B C 例2 十 x(x-1) x(x-1)2x-1 1=A(x-1)2+BC+(x-1)(1) 代入特殊值来确定系数A,B,C 取x=0,→A=1取x=1,→B=1 取x=2,并将A,B值代入(1)→C=-1 n=+ 2 ror 上页2 ( 1) 1 x x− , ( 1) 1 2 − + − = + x C x B x A 1 ( 1) ( 1) (1) 2 = A x − + Bx + Cx x − 代入特殊值来确定系数 A,B,C 取 x = 0,  A= 1 取 x = 1,  B = 1 取 x = 2, 并将 A,B 值代入 (1)  C = −1 . 1 1 ( 1) 1 1 2 − − − = + x x x 2 ( 1) 1 −  x x 例2