Cfrgtkky

How would you modify the following code so that I insert the arc indicated by the blue line in the diagram?
In the normal tikzpicture environment this seems to be quite straightforward, but I am unsure when it comes to graphs.

Thanks

documentclass{article}

usepackage[margin=0.5in]{geometry}

usepackage{pgfplots}

renewcommand{thesection}{arabic{section}}

usepackage{mathtools}

usepackage{cancel}

usepackage{pgfplots}

usepackage{amsmath}

newtheorem{theorem}{THEOREM}

newtheorem{proof}{PROOF}

usepackage{tikz}

usepackage{amssymb}

usetikzlibrary{patterns}

usepackage{fancyhdr}

usepackage{bigints}

usepackage{color}

usepackage{tcolorbox}

usepackage{color,xcolor}

usepackage{booktabs,array}

usepackage{hyperref}

usepackage{graphicx}

usetikzlibrary{arrows}

usepackage{polynom}

usepackage{wallpaper}

usetikzlibrary{shapes.geometric}

usepgfplotslibrary{fillbetween}

newenvironment{tightcenter}{

setlengthtopsep{0pt}

setlengthparskip{0pt}

begin{center}}{end{center}}

begin{document}

begin{tikzpicture}

begin{axis}[

axis x line=middle,    % put the x axis in the middle

axis y line=middle,    % put the y axis in the middle

axis line style=thick,

axis line style={->}, % arrows on the axis

xlabel={$x$},          % default put x on x-axis

ylabel={$y$},          % default put y on y-axis

ticks=none,

xmin=-7,xmax=7,

ymin=-7,ymax=7,

clip=false

]

%

draw[black,thick](axis cs:0,0) circle (1.7cm);

%

%

node [above] at (axis cs: +0.4,0){$O$};

node [left,scale=0.9] at (axis cs:  -0.5,-0.4){$theta$};

%

node [left,scale=0.9] at (axis cs: -2.4,-3.4){$(x,y)$};

%node [left] at (axis cs: 0,+1.5){$1$};

%node [left] at (axis cs: 0,-5.5){$-5$};

draw[black,thick](axis cs:0,0) -- (axis cs:-2.4,0) -- (axis cs:-2.4,-2.95) --cycle;

draw[black,thick](axis cs:-2.4,0) rectangle (axis cs:-2,-0.4);

draw[fill=black](axis cs:-2.4,-2.97) circle (0.4mm);

%

draw [thick](axis cs:0.92,2) ++(0:1) arc (185:264:0.5);

%draw [thick](axis cs:2.18,0) ++(0:1) arc (0:95:0.5);

end{axis}

end{tikzpicture}

end{document}

Sorry, there was a typo in my comment, it should have been draw [thick](axis cs:-0.5,0) arc (180:222:0.5);, i.e. a ,0 was missing. Here is the version using the angles library.

documentclass{article}

usepackage[margin=0.5in]{geometry}

usepackage{pgfplots}

pgfplotsset{compat=1.16}

usetikzlibrary{angles,quotes}

begin{document}

begin{tikzpicture}

begin{axis}[

axis x line=middle,    % put the x axis in the middle

axis y line=middle,    % put the y axis in the middle

axis line style=thick,

axis line style={->}, % arrows on the axis

xlabel={$x$},          % default put x on x-axis

ylabel={$y$},          % default put y on y-axis

ticks=none,

xmin=-7,xmax=7,

ymin=-7,ymax=7,

clip=false

]

%

draw[black,thick](0,0) coordinate (O) circle (1.7cm);

%

%

node [above] at ( +0.4,0){$O$};

%

node [left,scale=0.9] at ( -2.4,-3.4){$(x,y)$};

%node [left] at ( 0,+1.5){$1$};

%node [left] at ( 0,-5.5){$-5$};

draw[black,thick](0,0) -- (-2.4,0) coordinate (X) --

 (-2.4,-2.95) coordinate (xy)  --cycle;

draw[black,thick](-2.4,0) rectangle (-2,-0.4);

draw[fill=black](-2.4,-2.97) circle (0.4mm);

%

draw [thick](0.92,2) ++(0:1) arc (185:264:0.5);

%draw [thick](2.18,0) ++(0:1) arc (0:95:0.5);

path pic [draw,angle radius=0.5cm,"{$theta$}",angle eccentricity=1.5] {angle =

X--O--xy};

end{axis}

end{tikzpicture}

end{document}