[1-2+3-4+.+(2n-1)-2n]/(n-1)的极限我算出来-0.5,郁闷,
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![[1-2+3-4+.+(2n-1)-2n]/(n-1)的极限我算出来-0.5,郁闷,](/uploads/image/z/1747672-16-2.jpg?t=%5B1-2%2B3-4%2B.%2B%282n-1%29-2n%5D%2F%28n-1%29%E7%9A%84%E6%9E%81%E9%99%90%E6%88%91%E7%AE%97%E5%87%BA%E6%9D%A5-0.5%2C%E9%83%81%E9%97%B7%2C)
[1-2+3-4+.+(2n-1)-2n]/(n-1)的极限我算出来-0.5,郁闷,
[1-2+3-4+.+(2n-1)-2n]/(n-1)的极限
我算出来-0.5,郁闷,
[1-2+3-4+.+(2n-1)-2n]/(n-1)的极限我算出来-0.5,郁闷,
=[1-2+3-4+.+(2n-1)-2n]/(n-1)
=[1+3+5+7+……+(2n-1)]-[2+4+6+8+……+2n]
={(1+2n-1)×【(2n-1-1)/2+1】}/2-{(2+2n)×【(2n-2)/2+1】}/2
=n²-n-n²
=-n
1-2+3-4+.........+(2n-1)-2n = - n,
-n/(n-1) 极限为 -1