[(a²-b²)/(a²b-ab²)]÷[1+(a²+b²)/2ab]=[(a+b)(a-b)/ab(a-b)]÷[(2ab+a²+b²)/2ab]=[(a-b)/ab]÷[(a+b)²/2ab]=[(a-b)/ab]*[2ab/(a+b)²]=2(a-b)/(a+b)²希望采...