a2+ab-b2=0,且a,b均为正数,则(a2-b2)/(b-a)(b-2a)+(2a2-ab)/(4a2-4ab+b2）*(2a+b)/(2a-b)=

题目

a2+ab-b2=0,且a,b均为正数,则(a2-b2)/(b-a)(b-2a)+(2a2-ab)/(4a2-4ab+b2）*(2a+b)/(2a-b)=

答案

a²+ab-b²=0a²+ab+ b²/4- b²/4-b²=0(a+ b/2)²- 5b²/4=0(a+ b/2-√5b/2) (a+ b/2+√5b/2)=0a=(√5-1)b/2或a=(-√5-1)b/2a/b=(√5-1)/2或a/b=(-√5-1)/2(舍去,a,b均为正数)(a&...