(1)由4x^2+y^2=1y=x+m,可知5x^2+2mx+m^2-1=0∆=4m^2-20(m^2-1)≥ 0-√5/2≤m≤√5/2(2)设直线与圆的交点坐标为（x1,y1）、（x2,y2）,则x1+x2=-2m/5,x1x2=(m^2-1)/5d^2=(x1-x2)^2+(y1-y2)^2=2(x1-x2)^2=2[(x1+x2...