$\left(a+b\right)\left(c+d\right)=ac+ad+bc+bd$
tikz-pgf – How to Illustrate Double Distributive Property in LaTeX
tikz-arrowstikz-pgftikz-styles
Related Solutions
This already has the structure built in for you to provide other options to control the lines that are drawn. You can adjust the
out=to control the angle at the start of the arrow,in=to control the angle at the end of the arrow,distance=to control the height of the arrow,- and the two
shortento adjust how close the start and end are to the particular node.
There are probably other options, that should be in the PGF manual related to the syntax of using to instead of -- for line drawing.
Notes:
- I also moved the position of the in:
2\tikzmark{MarkB}xso that the arrow points to the center of the2xterm.
Code:
\documentclass{article}
\usepackage{amsmath}
\usepackage[dvipsnames]{xcolor}
\usepackage{tikz}
\usetikzlibrary{calc,shapes}
\newcommand{\tikzmark}[1]{\tikz[overlay,remember picture] \node (#1) {};}
\newcommand{\DrawBox}[2]{%
\begin{tikzpicture}[overlay,remember picture]
\draw[->,shorten >=5pt,shorten <=5pt,out=70,in=130,distance=0.5cm,#1] (MarkA.north) to (MarkC.north);
\draw[->,shorten >=5pt,shorten <=5pt,out=50,in=140,distance=0.3cm,#2] (MarkA.north) to (MarkB.north);
\end{tikzpicture}
}
\begin{document}
\[\tikzmark{MarkA}a(b\tikzmark{MarkB}+c\tikzmark{MarkC})=ab+ac \DrawBox{OrangeRed,distance=0.75cm,in=110,shorten >=3pt}{Cerulean,out=60,in=110,distance=0.5cm}\]
\begin{align*}
-(2x+5)&=(-\tikzmark{MarkA}1)(2\tikzmark{MarkB}x+5\tikzmark{MarkC})\DrawBox{OrangeRed,distance=0.75cm}{Cerulean,out=60,in=110,distance=0.5cm}\\
&=(-1)(2x)+(-1)(5)\\
&=-2x+(-5)\\
&=-2x-5
\end{align*}
\end{document}
The following code maybe a starting point for you:
\documentclass[]{article}
\usepackage[utf8]{inputenc}
\usepackage{tikz}
\newcounter{source}
\newcommand\source[1]{%
\tikz[remember picture,baseline,inner sep=0pt] {%
\node [name=source-\thesource,anchor=base]{$#1$};
}%
\setcounter{target}{0}
\stepcounter{source}
}
\newcounter{target}
\newcommand\target[1]{%
\tikz[remember picture,baseline,inner sep=0pt] {%
\node [name=target-\thetarget,anchor=base]{$#1$};
}%
\setcounter{source}{0}
\stepcounter{target}%
}
\newcommand\drawarrows{
\tikz[remember picture, overlay, bend left=45, -latex] {
\foreach \j [evaluate=\j as \m using int(\j)] in {1,...,\thesource}{
\foreach \i [evaluate=\i as \n using int(\i-1)] in {1,...,\thetarget} {
\draw [red](source-0.north) to (target-\n.north) coordinate (UP);
}
\node [red] at (UP) [above] {1};
}
}
\tikz[remember picture, overlay, bend left=-45, -latex] {
\foreach \j [evaluate=\j as \m using int(\j)] in {1,...,\thesource}{
\foreach \i [evaluate=\i as \n using int(\i-1)] in {1,...,\thetarget} {
\draw [blue](source-1.south) to (target-\n.south) coordinate (DOWN) ;
}
\node [blue] at (DOWN) [below] {2};
}
}
}
\begin{document}
\begin{equation}
(\source{a}+\source{4})(\target{b}+\target{3})=\mbox{\drawarrows}
\end{equation}
\end{document}
Output:
Update: Labeling each arrow:
\documentclass[]{article}
\usepackage[utf8]{inputenc}
\usepackage{tikz,pgfplots}
\newcounter{source}
\newcommand\source[1]{%
\tikz[remember picture,baseline,inner sep=0pt] {%
\node [name=source-\thesource,anchor=base]{$#1$};
}%
\setcounter{target}{0}
\stepcounter{source}
}
\newcounter{target}
\newcommand\target[1]{%
\tikz[remember picture,baseline,inner xsep=0pt] {%
\node [name=target-\thetarget,anchor=base]{$#1$};
}%
\setcounter{source}{0}
\stepcounter{target}%
}
\newcommand\drawarrows{
\tikz[remember picture, overlay, bend left=45, -latex] {
\foreach \j [evaluate=\j as \m using int(\j)] in {1,...,\thesource}{
\foreach \i [evaluate=\i as \n using int(\i-1)] in {1,...,\thetarget} {
\draw [red](source-0.north) to (target-\n.north) ;
\node [red] at ([xshift=-5mm]target-\n.north) [above=2mm] {\i};
}
}
}
\tikz[remember picture, overlay, bend left=-45, -latex] {
\foreach \j [evaluate=\j as \m using int(\j)] in {1,...,\thesource}{
\foreach \i [evaluate=\i as \n using int(\i-1)] in {1,...,\thetarget} {
\draw [blue](source-1.south) to (target-\n.south) ;
\pgfmathsetmacro{\ii}{\i+2)};
\node [blue] at ([xshift=-2mm]target-\n.south) [below=2mm] {\pgfmathprintnumber \ii};
}
}
}}
\begin{document}
\begin{equation}
(\source{a}+\source{4})(\target{b}+\target{3})=\mbox{\drawarrows}
\end{equation}
\end{document}
and the output:
Best Answer
Here's a solution using
tikzmarklibrary, instead of reinventing the wheel, like many old solutions you can find here.