1.a=2+根号3 b=2-根号3a²-b²/a²b+ab²÷（1- （ a²+b²/2ab）） =[(a+b)(a-b)]/[ab(a+b)]÷[-(a-b)²/2ab] =-[(a-b)/ab]×[2ab/(a-b)²]=-2/(a-b)=-2/(2+√3-2+√3）＝-1/√3＝...