Mathematics. Articles in English (et en français dans le futur).

The Fourier Transform of exp(-cx^2) and Its Convolution

We develop two almost straightforward way to compute the Fourier transform of $\exp(-cx^2)$, in the sense that any contour integration and the calculus of residues are not required at all. The first cool approach enables us to think about these elementary concepts much deeper, so I highly recommend to study this approach as long as you are familiar with ODE of first order.
The Fourier Transform of exp(-cx^2) and Its Convolution

Basic Facts of Semicontinuous Functions

Basic Facts of Semicontinuous Functions

洛必达法则的几种不同的证明

洛必达法则的几种不同的证明