先化简,再求值:(1-1/a+1)÷a²-a/a+1,其中a=2+√3
问题描述:
先化简,再求值:(1-1/a+1)÷a²-a/a+1,其中a=2+√3
答
:(1-1/a+1)÷a²-a/a+1
=[a/(a+1)]÷[(a(a-1)/(a+1)]
=[a/(a+1)]x[(a+1)/a(a-1)]
=1/(a-1)
=1/(1+√3)
=(√3-1)/2