# Table using array

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

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

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

• Off-topic (for this question): You don't need 20 columns; You don't need all the braces/\text{Leibnitz} would suffice; Why a textual table inside a math display equation? – Werner May 20 '14 at 5:51
• Dear Sir, text mentioned above is dummy; table is having around 18 rows. I pasted image and array with rough data. Regarding table inside a math display equation; I'm looking for tools using which even person without latex knowledge can practically work with it. In MathType there is a option to convert display code into Latex commands; so textual table is inside a math display equation. – Pawan Mude May 20 '14 at 6:10

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}