2/1+x - 2/1-x - 4x/(x^2)-1
點樣做??
點解個答案係1/1-x??
有條1985年mc唔識
2008-10-01 5:09 am
回答 (2)
2008-10-01 5:20 am
✔ 最佳答案
2/(1 + x) - 2/(1-x) - 4x/(x^2 - 1)= 2/(1 +x) - 2/(1-x) - 4x/[(1+ x)(x -1)]
= 2/(1+x) + 2/(x -1) - 4x/[(1+x)(x -1)]
= [2(x -1) + 2( 1 +x) - 4x]/[(1 + x)(x -1)]
= (2x - 2 + 2 + 2x - 4x)/[(1+x)(x-1)]
= 0.
probably there is some mistake in the question, please check.
2008-10-01 11:39 pm
2/(1 + x) - 2/(1-x) - 4x/(x^2 - 1)
= 2/(1 +x) - 2/(1-x) - 4x/[(1+ x)(x -1)]
= 2/(1+x) + 2/(x -1) - 4x/[(1+x)(x -1)]
= [2(x -1) + 2( 1 +x) - 4x]/[(1 + x)(x -1)]
= (2x - 2 + 2 + 2x - 4x)/[(1+x)(x-1)]
= 0.
There are some mistakes.
= 2/(1 +x) - 2/(1-x) - 4x/[(1+ x)(x -1)]
= 2/(1+x) + 2/(x -1) - 4x/[(1+x)(x -1)]
= [2(x -1) + 2( 1 +x) - 4x]/[(1 + x)(x -1)]
= (2x - 2 + 2 + 2x - 4x)/[(1+x)(x-1)]
= 0.
There are some mistakes.
參考: my maths knowledge
收錄日期: 2021-04-13 18:20:12
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