Exponential Continuous Probability Distribution

Exponential RV $X$ takes positive values according to PDF:

PDF

$$f(x,\lambda )=\{\begin{array}{ll}\lambda e^{-\lambda x}& x\ge 0\\ 0& x<0\end{array}$$

For some $\lambda >0$

CDF

$$F(x,\lambda )=\{\begin{array}{ll}1-e^{-\lambda x}& x\ge 0\\ 0& x<0\end{array}$$