√x＋√y=√ay=﹙√x－√a﹚²y'=2﹙√x－√a﹚／﹙2√x﹚=﹙√x－√a﹚／√x设P（m,﹙√m－√a﹚²﹚是√x＋√y=√a上任意一点,则以P为切点的切线方程是y-﹙√m－√a﹚²=﹙√m－√a﹚／√m·﹙x-m﹚y=...