y=(mx^2+4√3x+n)/(x^2+1) (m-y)x^2+4√3x+n-y=0 上方程未知数为x的判别式△≥0 即(4√3)^2-4(m-y)*(n-y)≥0 y^2-(m+n)y+mn-12≤0 [m+n-√(m^2+n^2-2mn+48)]/2≤y≤[m+n+√(m^2+n^2-2mn+48)]/2 已知y=(mx^2+4√3x+n)...