mathematica8.0中如何求带根号的函数最小值,
函数为z=10 Sqrt[(x - 1)^2 + (y - 5)^2] + 16 Sqrt[(x - 3)^2 + (y - 4)^2] +
6 Sqrt[(x - 5)^2 + (y - 3)^2] + 11 Sqrt[(x - 4)^2 + (y - 2)^2] +
7 Sqrt[(x - 2)^2 + (y - 1)^2] +
4 Sqrt[(x - 2)^2 + y^2];,1