Exponential distribution
| Notation | $x\sim \mathrm{Exp}(\lambda)$ |
| $\lambda\exp\left\{-\lambda x\right\}$ | |
| cdf | $1-\exp\left\{-\lambda x\right\}$ |
| EV | ${1\over\lambda}$ |
| Var | $\lambda^{-2}$ |
| Char. function | $\left(1 - \frac{it}{\lambda}\right)^{-1}$ |
| Entropy | $\log(\lambda)$ |
| Exponential family |