calc

*** QuickLaTeX cannot compile formula:
\begin{tikzpicture}

   \begin{axis}[
      xlabel=$x$,
      ylabel=$y$,
      zlabel=$f(x, y)$,
      domain=1:2,
      domain y=3:4,
      colormap/viridis,
      view={45}{30}, % Ajustez l'angle de vue si nécessaire
   ]
    \addplot3[surf, opacity=0.7, samples=25, samples y=25, shader=interp] {x^2*y};

    % Plan xy pour montrer l'aire sous la courbe
    \addplot3[surf, opacity=0.2, domain=1:2, domain y=3:4, fill=white] {0};

    % Lignes de contour sur le plan xy
    \addplot3[contour gnuplot={levels={0.5},labels=false},domain=1:2, domain y=3:4, thick] {0};
   \end{axis}
\end{tikzpicture}

*** Error message:
Package pgfkeys Error: I do not know the key '/tikz/y)$' and I am going to ignore it. Perhaps you misspelled it.
leading text:    \end{axis}
Extra }, or forgotten $.
leading text:    \end{axis}
Missing $ inserted.
leading text:    \end{axis}
Missing } inserted.
leading text:    \end{axis}
Package tikz Error: Giving up on this path. Did you forget a semicolon?.
leading text:    \end{axis}
Extra }, or forgotten \endgroup.
leading text:    \end{axis}
Missing } inserted.
leading text:    \end{axis}
Extra }, or forgotten \endgroup.
leading text:    \end{axis}
Missing } inserted.
leading text:    \end{axis}
Extra }, or forgotten \endgroup.
leading text:    \end{axis}
Extra }, or forgotten \endgroup.
leading text:    \end{axis}
Missing } inserted.