# Coordinate System in Tikz with plottet with one equation

I would like to have this coordinate system (with numbers on the axes): I know how to make it in Tikz; but the numbers on the axes are missing and I would like to add a plot:

\documentclass[border=10pt, tikz]{standalone}
\usepackage{pgfplots}
\usetikzlibrary{arrows,positioning}

\begin{document}
\tikzset{
>=stealth',
punkt/.style={
rectangle,
rounded corners,
draw=black, very thick,
text width=6.5em,
minimum height=2em,
text centered},
pil/.style={
->,
thick,
shorten <=2pt,
shorten >=2pt,}
}
\begin{tikzpicture}
\draw [pil] (4,0) -- (4,8);
\draw [pil] (0,4) -- (8,4);
\draw [gray, dashed, very thin] (0,0) grid (8,8);
\end{tikzpicture}

\end{document}


The equation of the plot:

((x/7)^2*sqrt(abs(abs(x)-3)/(abs(x)-3))+(y/3)^2*sqrt(abs(y+3/7*sqrt(33))/(y+3/7*sqrt(33)))-1)

I don't know how to add numbers on the x- and y-axis. And I don't know how to plot the graph.

Kind regards!

• pgfplots would be a better choice here. Would you be willing to switch? – Gonzalo Medina Jul 2 '15 at 23:58
• @GonzaloMedina I would, if I could. But I don't know how to make a coordinate system like the above. The coordinate systems in the Manual don't look the coordinate system I've made. :-) – Basilius Sapientia Jul 3 '15 at 0:31
• Does the equation have two independent variables x and y? Should not a two-variable function be plotted in a three-dimensional coordinate system? – Enthusiastic Engineer Jul 3 '15 at 8:20

For plots, use pgfplots; its great customization capabilities allow to easily adapt the style to the one you want: The code:

\documentclass[border=10pt, tikz]{standalone}
\usepackage{pgfplots}
\usetikzlibrary{arrows}

\tikzset{
>=stealth',
punkt/.style={
rectangle,
rounded corners,
draw=black, very thick,
text width=6.5em,
minimum height=2em,
text centered},
pil/.style={
->,
thick,
shorten <=2pt,
shorten >=2pt,}
}

\pgfplotsset{
grid style={gray, dashed, very thin},
every inner x axis line/.append style={pil},
every inner y axis line/.append style={pil},
}

\begin{document}

\begin{tikzpicture}
\begin{axis}[
axis lines=middle,
grid=major,
xmin=-4,
xmax=4,
ymin=-4,
ymax=4,
xtick={-4,-3,...,4},
ytick={-4,-3,...,4},
width=12cm,
height=12cm,
]