简便方法计算(过程)
问题描述:
简便方法计算(过程)
2008^2 -2007*2009
(11/2)^2 -2*(11/2) *(1/2) +(1/2)^2
答
2008^2 -2007*2009
=2008^2 -(2008-1)*(2008+1)
=2008^2 -(2008^2-1)
=2008^2-2008^2+1
=1
(11/2)^2 -2*(11/2) *(1/2) +(1/2)^2
=(11/2)^2 -(11/2) *2*(1/2) +(1/2)^2
=(11/2)^2 -11/2+(1/2)^2
=11/2*(11/2-1)+1/4
=11/2*9/2+1/4
=99/4+1/4
=100/4
=25