[Tex/LaTex] Table using array

arraystables

I'm creating Latex Tables using Array
One of the sample table is mentioned below with merging multi-cell of rows.

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Can you please help me to understand, how can i merges rows in arrays
Sample Latex table with Array is mentioned below;

\[\begin{array}{*{20}{|c}}
\hline
   {{\text{Differentiation}}} & {{\text{Integration}}} & {}  \\
   {{\text{The problem of finding SLOPE}}} & {} & {}  \\
   {} & {{\text{Leibnitz}}} & {{\text{Archimedes}}}  \\
   a & b & c  \\
   d & e & f  \\
   g & h & i  \\
   j & k & l  \\
   m & n & o  \\
\hline
\end{array} \]

Best Answer

This might be a starting point for you. I created a new column type P which makes it easier distributing the columns over the width of the textblock, because with this solution the widths of the n columns should add up to 1 and not to 1-n*\tabcolsep.

\documentclass{article}
\pagestyle{empty}% for cropping
\usepackage{booktabs,array}
\newcolumntype{P}[1]{>{\raggedright\arraybackslash}p{\dimexpr#1\linewidth-2\tabcolsep}}
\begin{document}
\begin{table}
  \centering
  \begin{tabular}{P{0.3}P{0.35}P{0.35}}
    \toprule
    Differentiation & \multicolumn{2}{c}{Integration} \\
    \midrule
    Slope & \multicolumn{2}{l}{Area} \\
    & Leibnitz & Archimedes, Eudoxus, others \\
    & Anti Deri & Area \\
    & Test 1 & Test 2 \\
    & Indefinite Integral & Definite Integral \\[\baselineskip]
    & \multicolumn{2}{c}{Together constitutes Integral Calculus} \\
    \midrule
    Derivative of a polynomial function decreases its degree by 1 & \multicolumn{2}{p{0.5\textwidth}}{Integral of a polynomial function increases its degree by 1} \\
    \bottomrule
  \end{tabular}
\end{table}
\end{document}

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