4a/(a^2-1)+(1+a)/(1-a)的结果是我算的是-(a^2-6a+1)/(a^2-1)

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4a/(a^2-1)+(1+a)/(1-a)的结果是我算的是-(a^2-6a+1)/(a^2-1)

4a/(a^2-1)+(1+a)/(1-a)的结果是我算的是-(a^2-6a+1)/(a^2-1)
4a/(a^2-1)+(1+a)/(1-a)的结果是
我算的是-(a^2-6a+1)/(a^2-1)

4a/(a^2-1)+(1+a)/(1-a)的结果是我算的是-(a^2-6a+1)/(a^2-1)
原式=4a/(a^2-1)+(1+a)^2/(1-a)(1+a)
=4a/(a^2-1)-(a+1)^2/(a^2-1).
=[4a-(a+1)^2]/(a^2-1)
= [4a-a^2-2a-1]/(a^2-1)
=-(a^2-2a+1)/(a^2-1)
=-(a-1)^2/(a+1)(a-1)
=-(a-1)/(a+1)
=(1-a)/(a+1)

=4a/(a^2-1)-(1+a)(a+1)/(a-1)(a+1)
=(4a-1-2a-a^2)/(a^2-1)
=-(a^2-2a+1)/(a^2-1)
=-(a-1)^2/(a-1)(a+1)
=-(a-1)/(a+1)
=(1-a)/(a+1)