Weibull distribution

$$ f(x) = \begin{cases} \frac{k}{\lambda}(\frac{x}{\lambda})^{k-1}e^{-(x/\lambda)^k}, & \text{if $x \geq 0$,} \\ 0, & \text{otherwise.} \end{cases} \\[24pt] \text{where $k$ is shape parameter and $\lambda$ is the scale parameter.} \\ $$