Question

若x=根号（2000*2001*2002*2003+1）则x的值是 A.1999 B.2000 C.2001 D2002

Answer 1

（根号下2000×2001×2002×2003+1）-2001²

=√[2001×2002×(2001-1)×(2002+1)+1]-2001²

=√[2001×2002×(2001×2002-2002+2001-1)+1]-2001²

=√[2001×2002×(2001×2002-2)+1]-2001²

=√[(2001×2002)²-2×(2001×2002)+1]-2001²

=√(2001×2002-1)²-2001²

=2001×2002-1-2001²

=2001X（2002-2001）-1

=2000

选择B