(a+1/a-1)-(a平方+a/a平方-1)
=(a+1/a-1）-[a(a+1)/(a+1)(a-1)]
=(a+1/a-1)-a/(a-1)
=(a+1-a)/(a-1)
=1/(a-1)
化简(a+1/a-1)-(a平方+a/a平方-1)
(a+1/a-1)-(a平方+a/a平方-1)
=(a+1/a-1）-[a(a+1)/(a+1)(a-1)]
=(a+1/a-1)-a/(a-1)
=(a+1-a)/(a-1)
=1/(a-1)