2x-4≠0,x≠2y=[（x-2）²+1]/2(x-2)= 1/2*(x-2)+ 1/[2(x-2)]=1/2*[x-2+ 1/(x-2)]当x＞2时y≥ 1/2*2=1,当x=3时,等号成立当x＜2时,y＜0-y= -1/2*[x-2+ 1/(x-2)]≥1故y≤ -1值域是 (-∞,-1]∪[1,+∞）...