x减二分之一加x加一分之二减x减一分之二减x加二分 - 知识问答

x减二分之一加x加一分之二减x减一分之二减x加二分之一等于?

2个回答

1/(x-2) + 2/(x+1) - 2/(x-1) - 1/(x+2)
= [1/(x-2) - 1/(x+2)] + [2/(x+1) - 2/(x-1)]
= 4/(x^2-4) - 4/(x^2-1)
= 4[1/(x^2-4) - 1/(x^2-1)]
= 4*3/[(x^2-4)(x^2-1)]
= 12/[(x^2-4)(x^2-1)]

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