(x+1)(x+2)(x+3)(x+4)+1
=[(x+1)(x+4)][(x+2)(x+3)]+1
=[(x^2+5x)+4][(x^2+5x)+6]+1
=(x^2+5x)^2+10(x^2+5x)+24+1
=(x^2+5x)^2+10(x^2+5x)+25
=(x^2+5x+5)^2
√（2003*2004*2005*2006+1）-2004的平方
=2002^2+5*2002+5-2004^2
=(2002+2004)(2002-2004)+10015
=2003