\documentclass{amsart}
\title{Madhava's series for $\frac{\pi}{4}$}
\usepackage{xfrac}
\usepackage{tikz}
\usetikzlibrary{positioning, calc,decorations.pathreplacing,intersections, through}
\begin{document}
\maketitle
\begin{center}
\begin{tikzpicture}[scale=3]
% The coordinates (0,0), (1,0)
\coordinate[label=below left:$0$] (O) at (0,0);
\coordinate[label=below left:$1$] (A) at (1,0);
%The Axes and the circle
\path [draw, dotted, thick, name path=C] (0,0) circle (1cm);
\draw[thick, domain=0:45] plot ({cos(\x)}, {sin(\x)});