2x-3x^2+1≥0
3x^2-2x-1≤0
(3x+1)(x-1)≤0
-1/3≤x≤1
x=(1-1/3)/2=1/3 y=(2x-3x^2+1)^1/2为最大值=2/3
y值域[0,2/3]