(x+a)/(x^2-2)=(x+a)/(x-根号2)(x+根号2)=1 若a=根号2 (x+根号2)/(x-根号2)(x+根号2)=1
1/(x-根号2)=1 x-根号2=1 x=1+根号2 x=1+根号2 x^2-2=3+2根号2-2=1+2根号2≠0
所以 a=根号2 满足条件 若a=-根号2 (x-根号2)/(x-根号2)(x+根号2)=1
1/(x+根号2)=1 x+根号2=1 x=1-根号2 x=1-根号2 x^2-2=3-2根号2-2=1-2根号2≠0 所以 a=-根号2 满足条件