The standard real gaussian density function is the D4364: Real function
\begin{equation}
\mathbb{R} \to \mathbb{R}, \quad
x \mapsto \frac{1}{\sqrt{2 \pi}} \exp \bigg( - \frac{1}{2} x^2 \bigg)
\end{equation}
The standard real gaussian density function is the D4364: Real function
\begin{equation}
\mathbb{R} \to \mathbb{R}, \quad
x \mapsto (2 \pi)^{- 1/2} e^{- x^2 / 2}
\end{equation}
The standard real gaussian density function is the D4364: Real function
\begin{equation}
\mathbb{R} \to \mathbb{R}, \quad
x \mapsto \frac{1}{\sqrt{2 \pi}} e^{- \frac{x^2}{2}}
\end{equation}