y>√1/2-x +√x-1/2 +1先由根号得：X≥1/2，X≤1/2，所以X=1/2√(y²-2y+1)/(y-1)=√(y-1)²/(y-1)=|y-1|y>√1/2-x +√x-1/2 +1=1,y>1|x-1|-√(x-1)² - √y²-2y+1/y-1=|x-1|-|x-1|-|y-1|=-|y-1|=-(y-1)-y+1
