题库搜索>问题求解PS-13124
If x ≠ 0, then (x + 1/x)2 - (x - 1/x)2 =
分析A选项
分析B选项
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分析D选项
分析E选项
平方差公式a^2-b^2=(a+b)(a-b)
化解原式=(x+1/x+x-1/x)*(x+1/x-x+1/x)=2x*2/x=4
lgw273862
可是(x+1/x+x-1/x)不是等于2吗,那算出来不应该是4/x
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