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標題: [Core] 1985 CE maths [打印本頁]

作者: chemqueen    時間: 2017-2-19 05:37 PM     標題: 1985 CE maths

想問 1985 CE MATHs Paper 2 Q.1 點計?

2/1+x  -   2/ 1-x  -  4x/ x*2-1 = ?  點解計極都係0?


因為solution 冇,求解答
作者: lscdbs    時間: 2017-2-20 03:53 PM

yes you are correct, the answer is 0
作者: 數痴夢王    時間: 2017-2-27 03:20 PM

2/(1+x)  -   2/(1-x)  -  4x/(x^2-1)
= 2/(x+1) +   2/(x-1)  -  4x/(x^2-1)
= 2(x-1)/(x^2-1) + 2(x+1)/(x^2-1)  -  4x/(x^2-1)
= (2x-2+2x+2-4x)/(x^2-1)
= 0/(x^2-1)
= 0




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