1/a-b+1/a+b+2a/(a^2+b^2)+4a^3/(a^4+b^4)
分式加减,帮忙! ( )内为分母
参考答案:(a+b)(a-b)=a²-b²
(a²-b²)(a²+b²)=a^4-b^4
(a^4+b^4)(a^4-b^4)=a^8-b^8
有什么感想？
[1/(a-b)]+[1/(a+b)]+[2a/(a^2+b^2)]+[4a^3/(a^4+b^4)]
=[2a/(a^2-b^2)]+[2a/(a^2+b^2)]+[4a^3/(a^4+b^4)]
=[4a^3/(a^4-b^4)]+[4a^3/(a^4+b^4)]
=8a^7/(a^8-b^8)