(2002的平方-2*2002^2-2000)/2002^3+2002^2-2003

题目

(2002的平方-2*2002^2-2000)/2002^3+2002^2-2003

答案

令a=2002
2003=a+1
2000=a-2
原式=[a²(a-2)-(a-2)]/[a²(a+1)-(a+1)]
=(a-2)(a²-1)/(a+1)/(a²-1)
=(a-2)/(a+1)
=2000/2003