2011²+2013²-2分之2012²
4个回答

答案是1/2;

2013²=﹙2011+2﹚²=2011²+4×2011+4;

2013²-2=2011²+4×2011+4-2=2011²+4×2011+2;

2012²=﹙2011+1﹚²=2011²+2×2011+1;

2012²/﹙2011²+2013²﹣2﹚

=﹙2011²+2×2011+1﹚/﹙2×2011²+4×2011+2﹚

=﹙2011²+2×2011+1﹚/[2×﹙2011²+2×2011+1﹚]

=1/2

=0.5