f(x)=log2(mx^2+(m+2)x+m+2),若其值域为R,求实数x的取值范围

f(x)=log2(mx^2+(m+2)x+m+2),若其值域为R,求实数x的取值范围
f(x)=log2(mx^2+(m+2)x+m+2),若其值域为R,求实数x的取值范围

f(x)=log2(mx^2+(m+2)x+m+2),若其值域为R,求实数x的取值范围
应该是求实数m的取值范围吧?
m>o,且△=(m+2)^2-4m(m+2)=-3m^2-4m+4≥0
m>0,且3m^2+4m-4≤0
m>0,且(3m-2)(m+2)≤0
m>0,且-2≤m≤2/3
∴0即实数m的取值范围为(0,2/3]