[求助] 数学分析 已有1人参与

5楼: Originally posted by hank612 at 2016-06-12 13:10:25
令G(x)=\int_{0}^x g(t)dt, 由题设条件\int_{0}^1 g(x)dx=0知道 G(x)是周期为1的可微函数， 且G(n)=0.

于是分部积分， na_n=G(nx)f(x)|_0^1-\int_{0}^1 G(nx)f^{\prime}(x)dx
等于-\sum_{k=0}^{n-1}\int_{k}^{k ...

3楼: Originally posted by 哈哈笑泥 at 2016-06-11 22:48:10
n→∞，∫f(x)sin(nx)dx→0