先化简,再求值:[(x-y)2+(x+y)(x-y)]÷2x.其中x=2011,y=2010.
问题描述:
先化简,再求值:[(x-y)2+(x+y)(x-y)]÷2x.其中x=2011,y=2010.
答
[(x-y)2+(x+y)(x-y)]÷2x,
=[x2-2xy+y2+x2-y2]÷2x,
=(2x2-2xy)÷2x,
=x-y,
当x=2011,y=2010时,
原式=2011-2010=1.