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x是n的平方,问x的因子个数.
Suppose a number X = n^2
Then among all the factors of X, only one factor n when times itself (n^2) equals X. The rest are in pairs, the product of which equals X. For the paired factors, one is greater than n, while the other is smaller than n. So the total number of factors of X excluding n, is an even number because all of them exist in pairs.
Therefore, the total number of factors for X, when X = n^2, is an odd number.
Based on the above reason, only condition 1 is always correct. |
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