Question

先化简，再求值：（1-1/a+1)÷a²-a/a+1,其中a=2+√3

Answer 1

：（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

Answer 2

(1-1/（a+1）÷（a²-a/（a+1）=a/（a+1）×（a+1)/a(a-1）=1/（a-1).。 所以当a=2+根3时，原式=1/（根3+1）=（根3-1）/2.。