根号下大于等于0
2-(x+3)/(x+1)>=0
(2x+2-x-3)/(x+1)>=0
(x-1)/(x+1)>=0
所以 (x-1)(x+1)>=0
x<=-1,x>=1
分母x+1≠0
所以(-∞,-1)∪(1,+∞)