(1):x,y,z∈R+,x2+y2+z2=1,求S=xyz+yzx+xzy的最小值(1):x,y,z \in \mathbb R ^ +, x^2+y^2+z^2=1,求S = \frac{xy}{z} + \frac{yz}{x} + \frac{xz}{y}的最小值(1):x,y,z∈R+,x2+y2+z2=1,求S=zxy+xyz+yxz的最小值 (2):x,y,z∈R+,x+y+z=1,求证x4y(1−y2)+y4z(1−z2)+z4x(1−x2)≥18(2):x,y,z \in \mathbb R ^ +, x+y+z=1,求证\frac{x^4}{y(1-y^2)} + \frac{y^4}{z(1-z^2)} + \frac{z^4}{x(1-x^2)} \ge \frac{1}{8}(2):x,y,z∈R+,x+y+z=1,求证y(1−y2)x4+z(1−z2)y4+x(1−x2)z4≥81 求思路点拨
