5. 已知幂函数的图象过(12,24)(\frac{1}{2},\frac{\sqrt{2}}{4})(21,42),P(x1P(x_{1}P(x1,y1)y_{1})y1),Q(x2Q(x_{2}Q(x2,y2)(x1<x2)y_{2})(x_{1}<x_{2})y2)(x1<x2)是函数图象上的任意不同两点,则下列结论中正确的是((( )))