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{{ latex:numerical_sine.png ? 1500 }}
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\documentclass[border=3pt,tikz]{standalone}
\usepackage{amsmath,amssymb}
\usepackage{bm} % math bold
\usepackage[outline]{contour} % glow around text
\contourlength{1.2pt}
\usepackage{tikz}
\usetikzlibrary{patterns}
\tikzset{>=latex}
\begin{document}
% NUMERICAL SOLUTIONS
\begin{tikzpicture}[scale=1.5,xscale=1/80]
\def\N{60}
\def\xmin{-10} \def\xmax{320}
\def\ymin{-1.2} \def\ymax{1.2}
\def\tmin{-10} \def\tmax{300}
\def\blue{black!50!blue}, \def\red{black!50!red}
\def\value{0.765}
\def\Dtheta{20}
% axes
\draw[->,thick]
(\xmin,0) -- (\xmax,0)
node[anchor=north west] {$\theta$};
\draw[->,thick]
(0,\ymin) -- (0,\ymax)
node[anchor=south east] {$y$};
% plots
\draw[thick,\blue,variable=\t,domain=\tmin:\tmax,samples=\N,smooth]
plot (\t,{sin(2*\t)});
\draw[thick,\red,variable=\t,domain=\tmin:\tmax,samples=\N,smooth]
plot (\t,\value);
% function labels
\node[\blue,above right=1pt,scale=0.9] at (45,1) {$y=\sin2\theta$};
\node[\red, below=1pt,scale=0.9] at (135,\value) {$y=\value$};
% numerical solutions
\draw[dashed,thick] (45-\Dtheta,-\value*0.05) -- (45-\Dtheta,\value*1.05);
\draw[dashed,thick] (45+\Dtheta,-\value*0.05) -- (45+\Dtheta,\value*1.05);
% ticks
\foreach \x in {45,90,135,180,225,270}{
\draw[thick]
(\x,0.05) -- (\x,-0.05) node[below,scale=0.9] {\contour{white}{$\x^\circ$}};}
\foreach \y in {1,-1}{
\draw[thick]
(4,\y) -- (-4,\y) node[left,scale=0.9] {$\y$};}
\end{tikzpicture}
\end{document}