x+2=1/xx²+2x=11/(x+1)-(x+3)/(x的平方-1)×(x的平方-2x+1)/(x的平方+4x+3)=1/(x+1)-(x+3)/(x+1)(x-1) x (x-1)²/（x+1）（x+3） =1/(x+1)-(x-1)/(x+1) ²=(x+1-x+1)/(x+1)²=2/(x+1)²=2/(x&#...