显然x不等于1,分之分母同乘x-1
(√(x+3) - 2)/(√x -1)
=(√(x+3) - 2)(x-1)/(√x -1)(x-1)
=(√(x+3) - 2)(√x+1)(√x-1)/(√x -1)(√x+3 -2)(√x+3 +2)
=(√x+1)/(√x+3 +2)
所以x趋向于1 时(√(x+3) - 2)/(√x -1)的极限为(1+1)/(2+2)=1/2
显然x不等于1,分之分母同乘x-1
(√(x+3) - 2)/(√x -1)
=(√(x+3) - 2)(x-1)/(√x -1)(x-1)
=(√(x+3) - 2)(√x+1)(√x-1)/(√x -1)(√x+3 -2)(√x+3 +2)
=(√x+1)/(√x+3 +2)
所以x趋向于1 时(√(x+3) - 2)/(√x -1)的极限为(1+1)/(2+2)=1/2