已知0已知0
已知0解y=(1-2x)x=-2x²+x=-2(x-1/4)²+1/8由0知当x=1/4时,y有最大值y=-2(1/4-1/4)²+1/8=1/8
y=1/2 [ (1-2x) * 2x]<=1/2 [ 1/4 (1-2x+2x)^2]=1/8说明: (a-b)^2>=0 得到 (a+b)^2/4>=|ab|