y=x+√（1-2x)=x-1/2+√(1-2x)+1/2=(-1/2)(1-2x)+√(1-2x)+1/2令t=√（1-2x）,则t>=0y=(-1/2)t^2+t+1/2=(-1/2)(t^2-2t+1)+1=(-1/2)(t-1)^2+1当t=1时,即x=0时,ymax=1当t=0或t=3时,y=1/2当t趋向于正无穷大时,y趋向于负...