1.limn→∞∑i=1n−1imnm+1\lim \limits_{n\to \infty}\frac{\sum_{i=1}^{n-1}i^m}{n^{m+1}}n→∞limnm+1∑i=1n−1im
2.limn→∞(nn/2)2n\lim \limits_{n\to \infty}\frac{\binom{n}{n/2}}{2^n}n→∞lim2n(n/2n)
3.a,ba,ba,b 都是正整数,且满足(ab+1)∣(a2+b2)(ab+1)|(a^2 + b^2)(ab+1)∣(a2+b2),求证a2+b2ab+1\frac{a^2+b^2}{ab+1}ab+1a2+b2为平方数
4.自己证明 limn→∞∑i=1n1i−lnn\lim \limits_{n\to \infty}\sum_{i=1}^n{\frac{1}{i}}-\ln nn→∞lim∑i=1ni1−lnn