a/(a-根号下ab)-根号b/(根号下a+根号b)=(2+根号3)/[2+根号3-根号(2+根号3)(2-根号3)]-(2-根号3)/(2+根号3+2-根号3)=(2+根号3)/[2+根号3-1]-(2-根号3)/4=(2+根号3)/(根号3+1)-(2-根号3)/4=(1+根号3)/2-(2-根号3)/4=3/...