x(1-2x)
=x-2x^2
=-2(x^2-x/2)
=-2(x-1/4)^2+1/8
当x=1/4时,
x(1-2x)的值最大1/8 x(1-2x)
=x-2x^2
=-2(x^2-x/2)
=-2(x-1/4)^2+1/8
当x=1/4时,
x(1-2x)的值最大1/8