2002的3次方+2*2002的平方+2002/2003的3次方-2*2003的2次方+2003
=2002(2002²+2x2002+1)/ 2003(2003²-2x2003+1)
=2002(2002+1)²/2003(2003-1)²
=2002*2003²/2003*2002²
=2003/2002
2002的3次方+2*2002的平方+2002/2003的3次方-2*2003的2次方+2003
=2002(2002²+2x2002+1)/ 2003(2003²-2x2003+1)
=2002(2002+1)²/2003(2003-1)²
=2002*2003²/2003*2002²
=2003/2002