Fourier

A relatively direct method is expounded in this paper to prove the termwise differentiation of power series, and a simple method is expressed to calculate the Fourier coefficient.

用比较接方法证明幂级数和函数在收敛域内可以逐项微公式；并得到了计算傅立系数一种简便方法.

By using the method of coordination transformation and expandedness Fourier series, an analytic solution is obtained from studying the Newtonian fluids laminar flow in eccentric anulus.

采用坐标变换和函数展开成傅立级数方法,推导出了牛顿流体偏心环空轴向流动速度场严格数学解解.

It is proved that the substitituon mapping is a proper Fourier integral operator with generalized hypoellipticity.

证明了变量替换映射是一个具广义亚椭园性适富里积算子。