Question

计算1/(x+1)+1/(1-x)的结果为()

Answer 1

原式=(1-x+x+1)/(1+x)(1-x)
=2/(1-x²)

追问

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Answer 2

1/(x+1)+1/(1-x)
=(x-1)/(x²-1)-(x+1)/(x²-1)
=-2/(x²-1)

Answer 3

2/1-x2