Let $T \in \text{Exp}(\theta)$ be a D4000: Standard exponential random positive real number.
Let $t \in \mathbb{R}$ be a D993: Real number.
Let $t \in \mathbb{R}$ be a D993: Real number.
Then
\begin{equation}
\mathbb{P}(T \leq t)
= \left( 1 - e^{- t} \right) I_{t \in [0, \infty)}
\end{equation}