Find Lim n → + ∞ (1 / N ^ k + 2 / N ^ k + + n / N ^ k) There are three situations,

Find Lim n → + ∞ (1 / N ^ k + 2 / N ^ k + + n / N ^ k) There are three situations,

The order of molecules can be obtained as 2 by summation of arithmetic sequence, so when k = 2, the original formula becomes (1 / 2 * (n ^ 2-N)) / N ^ 2, when n tends to infinity, the limit is 1 / 2, when k is greater than 2, the denominator tends to infinity faster, when k is less than 2, the original formula becomes infinity