作业帮初2分式数学题(1/a+1/b)^2/(1/a^2-1/b^2)已知答案`求步骤`详细给分
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初2分式数学题(1/a+1/b)^2/(1/a^2-1/b^2)已知答案`求步骤`详细给分
初2分式数学题
(1/a+1/b)^2/(1/a^2-1/b^2)已知答案`求步骤`详细给分
初2分式数学题(1/a+1/b)^2/(1/a^2-1/b^2)已知答案`求步骤`详细给分
(1/a+1/b)^2/(1/a^2-1/b^2)
=(1/a+1/b)²/(1/a+1/b)(1/a-1/b)
=(1/a+1/b)/(1/a-1/b)
=(b+a)/(b-a)
(1/a+1/b)^2/(1/a^2-1/b^2)
=(1/a+1/b)(1/a+1/b)(1/a+1/b)(1/a-1/b)
=(1/a+1/b)^3(1/a-1/b)
因为(a+b)^3=a^3+b^3+3ba^2+3ab^2
=1/a^4-1/b^4+(2/a^3) *1/b-(2/a)*1/b^3
分子通分得（A+B)*2/A*2B*2 分母通分（B*2-A*2)/A*2B*2 约分得（A+B)*2/(B*2-A*2) 约分（a+b）/(B-A)
楼主你好，解答如下：
(1/a+1/b)^2/(1/a^2-1/b^2)
=(1/a+1/b)^2/(1/a+1/b)(1/a-1/b)
=(1/a+1/b)/(1/a-1/b)
=[(a+b)/ab]/[(b-a)/ab]
=(b+a)/(b-a)
够详细吗？
(1/a+1/b)^2/(1/a^2-1/b^2)
=(1/a+1/b)^2/(1^2/a^2-1^2/b^2)
=(1/a+1/b)^2 / (1/a + 1^b) (1/a - 1/b)
原因 **X^2 - Y^2 = (X+Y)(X-Y) **
=(1/a + 1/b) / (1/a - 1/b)
=(1/a+1/b) / (1/a-1/b)
=(a-b) / (a+b)