利用Taylor公式f(x)=f(x.)+f'(x.)(x-x.)+f''(x.)/2!•(x-x.)^2,+f'''(x.)/3!•(x-x.)^3+……+f(n)(x.)/n!•(x-x.)^n+……f(x)=1/(x^2+3x+2)=1/(x+1)+1/(x+2)1/(x+1)=-[(1/3)+(X+4)/3^2+(X+4)^2/3^3+(...