1/a-1 -4/a的平方－4,其中a＝1／2=1/(a-1)-4/(a^2-4)=1/(a-1)-4/(a+2)(a-2)=1/(a-1)-[1/(a-2)-1/(a+2)]=1/(1-1/2)-[1/(1/2-2)-1/(1/2+2)]=2-[-2/3-2/5]=2+16/15=46/154x的3次方+4x的2次方+x =x(4x^2+4x+1)=x(2x+1)^2...