1/[x(x^3+2)=(1/2)[1/x-x^2/(x^3+2)] ∴原式=(1/2)∫dx/x-(1/2)∫x^2dx/(x^3+2) =(1/2)ln|x|-(1/2)(1/3)∫ d(x^3+2)/(x^3+2) =(1/2)ln|x|-(1/6)ln|x^3+2|+C. 注:用
待定系数法,求出分子的系数, 设1/[x(x^3+2)=A/x+(Bx^2+Cx+D)/(x^3+2), 得A=1/2,B=-1/2,C=0,D=0, ∴1/[x(x^3+2)]=1/(2x)-(1/2)x^2/(x^3+2).