\input{preamble-standalone.ltx}
\begin{document}

% Ex. No. 96 (Section 13.3.2 : Vertical line and value calculated by \tkzname{xfp} )

\begin{tikzpicture}
  \tkzInit[xmax=7,ymin=-1,ymax=1]
  \foreach\v in {1,2}
  {\tkzVLine[color=red]{\v*pi}}
  \tkzDrawY
  \tkzAxeX[trig=2]
  \tkzLabelY
\end{tikzpicture}

\end{document}