若抛物线y=x^2上存在A、B关于直线y=m(x+3/4)对称求实数m的取值范围

设AB:y=-x/m+b,代入y=x^得x^+x/m-b=0,设A(x1,y1),B(x2,y2),则x1+x2=-1/m,于是AB的中点C(-1/(2m),1/(2m^)+b)满足y>x^:1/(2m^)+b>[-1/(2m)]^,且在直线y=m(x+3/4)上：1/(2m^)+b=m[-1/(2m)+3/4],∴m[-1/(2m)+3/4]>1/(4m^...