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

% Ex. No. 93 (Section 13.1.2 : Horizontal line and value calculated by \tkzname{xfp} )

\begin{tikzpicture}
  \tkzInit[xmin=-3,xmax=3,ymin=-2,ymax=1.5]
  \foreach\v in {-1,1}
  {\tkzHLine[color=red]{\v*pi/2}}
  \tkzDrawY
  \tkzAxeX[trig=2]
  \tkzLabelY
\end{tikzpicture}

\end{document}