No package is required to print the varphi symbol in a latex document. You just need to use the default command \varphi.
| Symbol/Unicode | Varphi/U+1D711 |
|---|---|
| Type of symbol | Greek small letter |
| Package (requirement) | No |
| Argument | No |
| Latex command | \varphi |
| Example | \varphi βΒ π |
\documentclass{article}
\begin{document}
$$ \varphi x(t)=\mathrm{E}\left[e^{itX}\right] $$
$$ \varphi x(-it)=M_X (t) $$
$$ \varphi _{X}(t)=\mathrm{E}\left[\exp \left(i\int _{\mathbf {R} }t(s)X(s)\,ds\right)\right] $$
\end{document}Output :
