Table with multi rows and columns

Question

I can do the table in figure: I wrote this code but I can not fix the left and bottom side.

\documentclass{tufte-handout}

\usepackage{multirow}
\usepackage[italian]{babel}
\usepackage[utf8]{inputenc}
\usepackage{booktabs} 

\begin{document}
    \begin{fullwidth}
        \begin{center}
            \begin{tabular}{lccc}
                \toprule
                \multirow{2}*{Elemento} & \multicolumn{3}{c}{FUNZIONI TRASCENDENTI} \\
                \cmidrule(lr){2-4}
                & LOGARITMICHE & ESPONENZIALI & LOGARITMICHE \\
                \midrule

                \bottomrule
            \end{tabular}
        \end{center}
    \end{fullwidth}
\end{document}

Answer 1

edit:

• it seems that on the answer forgot as op as well me :-(.
• today i recognized, that the loaded mwe is not complete ... and that CarLaTeX ask me in her comment (which seems that i overlooked). i'm very sorry for this.
• now i add missing part of mwe: : \begin{document}, \begin{fullwidth} and definitions of used lengths,
• beside this i add showframe package to for show page layout (which had to be removed in real document)

now mwe works as expected (tested).

\documentclass{tufte-handout}

\usepackage{multirow}
\usepackage[italian]{babel}
\usepackage[utf8]{inputenc}
\usepackage{booktabs,tabularx}
    \newcolumntype{P}[1]{>{\centering\arraybackslash}p{#1}}    
\newlength\lengtha % width of two-columm multicolumn
\newlength\lengthb % width of four-columm multicolumn
\newlength\lengthc % width of six-columm multicolumn
%
\setlength\aboverulesep{0pt}
\setlength\belowrulesep{0pt}

%-------------------------------- show page layout, only for test
\usepackage{showframe}
\renewcommand\ShowFrameLinethickness{0.15pt}
\renewcommand*\ShowFrameColor{\color{red}}
%---------------------------------------------------------------%

\begin{document}
\begin{fullwidth}
\setlength\lengtha{\dimexpr.2\hsize+2\tabcolsep-2\arrayrulewidth\relax}
\setlength\lengthb{\dimexpr.4\hsize+6\tabcolsep-4\arrayrulewidth\relax}
\setlength\lengthc{\dimexpr.6\hsize+10\tabcolsep-6\arrayrulewidth\relax}
    \begin{tabularx}{\linewidth}{|*{10}{C|} }
    \toprule
\multicolumn{4}{|P{\lengthb}|}{Elemento}
                &   \multicolumn{6}{P{\lengthc}|}{FUNZIONI TRASCENDENTI}    \\
    \midrule
\multicolumn{2}{|P{\lengtha}|}{?}
    &   \multicolumn{2}{P{\lengtha}|}{?}
        &   \multicolumn{2}{P{\lengtha}|}{LOGARITMICHE}
            &   \multicolumn{2}{P{\lengtha}|}{ESPONENZIALI}
                &   \multicolumn{2}{P{\lengtha}|}{LOGARITMICHE}    \\
    \midrule
    &   &   &   &   &   &   &   &   &   \\
    \bottomrule
            \end{tabularx}
    \end{fullwidth}
\end{document}

Actually I reproduce showed picture of table and text from your MWE place as you can see from above image. I'm not sure if I guess correctly what you like to obtain.