y=|x|√(1-x)= √[x^2*(1-x)],
x^2*(1-x)=(1/2)*x*x*(2-2x)
≤(1/2)*{[ x+x+(2-2x)]/3}^3
=4/27,
所以y≤√(4/27)=2√3/9.
函数值域是[0,2√3/9].