你的叙述有问题:
(a²+a-2)/(a-1)-(a²-2a+1)/(a²-a)
=(a+2)(a-1)/(a-1)-(a-1)²/a(a-1)
=a+2-(a-1)/a
=(a²+2a-a+1)/a
=(a²+a+1)/a,
当a=√3-1,a²=(√3-1)²=3-2√3+1=4-2√3代入:
(a²+a+1)/a
=(4-2√3+√3-1+1)/(√3-1)
=(4-√3)/(√3-1)
=(4-√3)(√3+1)/(√3-1)(√3+1)
=(4√3+4-3-√3)/2
=(3√3+1)/2