# Unable to fill color in intersection area of two parabolas $y =x^2, x =y^2$ with tikz using the given code

Unable to fill color in intersection area of two parablolas $y =x^2, x =y^2$ with the given code. Please help ..

\documentclass{article}
\usepackage{tikz,pgfplots}
%\usepackage[x11names]{xcolor}
\usepackage{tikz}
\usetikzlibrary{intersections}
\pgfdeclarelayer{bg}    % declare background
\pgfsetlayers{bg,main}  % order of layers (main = standard layer)
\pgfplotsset{compat=1.13}
\usepackage{amsmath}
\usetikzlibrary{positioning}

\begin{document}

\begin{tikzpicture}[domain=0:2, scale = 0.75, dot/.style={circle,fill,inner sep=1pt}]
\draw(-4,0)--(4,0);
\draw (0,-4)--(0,4);
\draw[black, line width = 0.50mm]   plot[smooth,domain=-2:2] (\x, {(\x)^2});

\draw[blue,line width = 0.50mm]   plot[smooth,domain= -2:2,variable=\y]
( {(\y)^2},\y);
%\draw[black, line width = 0.50mm]   plot[smooth,domain= -2:2] (\y,  {(\y)^2});
\draw(2,3)node($y=x^2$){$y=x^2$};
\draw(5,2)node($x=y^2$){$x=y^2$};
\draw [left=.2cm](0,0)node(o){O};
\draw[right=.1cm](1,1)node(a){A};

\begin{pgfonlayer}{bg}    % select background
\path [fill=blue!50] (o.center) --(a.center)--cycle;

\end{pgfonlayer}
\end{tikzpicture}

\end{document}


Here you can just use \clip and \fill.

\documentclass{article}
\usepackage{tikz}
\pgfdeclarelayer{bg}    % declare background
\pgfsetlayers{bg,main}  % order of layers (main = standard layer)
\begin{document}
\begin{tikzpicture}[domain=0:2, scale = 0.75, dot/.style={circle,fill,inner sep=1pt}]
\draw(-4,0)--(4,0);
\draw (0,-4)--(0,4);
\draw[black, line width = 0.50mm]   plot[smooth,domain=-2:2] (\x, {(\x)^2});
\draw[blue,line width = 0.50mm]   plot[smooth,domain= -2:2,variable=\y]
( {(\y)^2},\y);
\draw(2,4)node[above]{$y=x^2$};
\draw(4,2)node[right,blue]{$x=y^2$};
\draw [left=.2cm](0,0)node[below left]{O};
\draw[right=.1cm](1,1)node(a){A};

\begin{pgfonlayer}{bg}    % select background
\clip plot[smooth,domain=-2:2] (\x, {(\x)^2});
\fill[red]  plot[smooth,domain= -2:2,variable=\y] ({(\y)^2},\y);
\end{pgfonlayer}
\end{tikzpicture}
\end{document}


However, in more complex situations you may be better off with the pgfplots fillbetween library.

\documentclass{article}
\usepackage{pgfplots}
\pgfplotsset{compat=1.16}
\usepgfplotslibrary{fillbetween}
\begin{document}
\begin{tikzpicture}
\begin{axis}[axis lines=middle,domain= -2:2,xtick=\empty,ytick=\empty,
clip=false,set layers,axis equal]
\addplot[color=black, line width = 0.50mm,name path=A]   {x^2}
node[pos=1,above]{$y=x^2$};
\addplot[color=blue, line width = 0.50mm,name path=B]   (x*x,x)
node[pos=1,above]{$x=y^2$};
\pgfonlayer{pre main}
\fill [red,intersection segments={of=A and B,
sequence={A1 -- B1[reverse]}, },];
\endpgfonlayer
\end{axis}
\end{tikzpicture}
\end{document}


• That is really great..... I am very thankful to you.... Really amazing... thanks a lot.... God bless you.... – Sachin Mar 26 '20 at 9:07