4-√4<4-√3<4-√1
2<4-√3<3
4-√3介于2~3之间
a=(4-√3)-2=2-√3
[(a²+a-2)/(a²+4a+4) +a/(a²+2a)]×(a- 4/a)
=[(a+2)(a-1)/(a+2)²+a/a(a+2)]×[(a²-4)/a]
=[(a-1)/(a+2)+1/(a+2)]×[(a+2)(a-2)/a]
=[a/(a+2)][(a+2)(a-2)/a]
=a-2
=2-√3-2
=-√3