分子最后一项应该是-2000吧
令a=2002
则2003=a+1
2000=a-2
原式=[a³-2a²-(a-2)]/[a³+a²-(a+1)]
=[a²(a-2)-(a-2)]/[a²(a+1)-(a+1)]
=(a-2)(a²-1)/[(a+1)/(a²-1)]
=(a-2)/(a+1)
=2000/2003
分子最后一项应该是-2000吧
令a=2002
则2003=a+1
2000=a-2
原式=[a³-2a²-(a-2)]/[a³+a²-(a+1)]
=[a²(a-2)-(a-2)]/[a²(a+1)-(a+1)]
=(a-2)(a²-1)/[(a+1)/(a²-1)]
=(a-2)/(a+1)
=2000/2003