2

I would like to plot a sampled sine wave. MWE is below. The error is that \hoek and \sinus are not defined.

\documentclass[12pt]{article}

\usepackage{tikz}
\usepackage{pgfplots}


\begin{document}


\begin{tikzpicture}
\begin{axis}[]
\addplot [domain=0:360,mark=none,samples=201,red]{0.5*sin(x)+0.5};
\foreach \count in {0.0,1.0,...,16.0}{%


\pgfmathsetmacro{\hoek}{\count*360.0/16.0};
\pgfmathsetmacro{\sinus}{0.5*sin(\count*360.0/16.0)+0.5};
\draw (\hoek,\sinus) circle[radius=2pt];



}
\end{axis}
\end{tikzpicture}
\end{document}
Jesse op den Brouw
  • 1,280

1 Answers1

6
  • \foreach loop doesn't work (well) in the pgfplots diagrams.
  • Samples can be simply drawn by use ycomb option:
\documentclass[12pt]{article}
\usepackage{pgfplots}

\begin{document}


\begin{tikzpicture}
\begin{axis}
\addplot [red, domain=0:360,mark=none,samples=201] {0.5sin(x)+0.5};
\addplot [ycomb, red, domain=0:360, 
          mark=, samples=18] {0.5*sin(x)+0.5};
\end{axis}
\end{tikzpicture}
\end{document}

enter image description here

Edit: A bit more fancy diagram, For fun and exercise ...

enter image description here

\documentclass[12pt, margin=3mm]{standalone}
\usepackage{pgfplots}

\begin{document}
    \begin{tikzpicture}
\begin{axis}[
x = 0.8,
xtick={0,30,...,360},
extra y ticks={0, 0.5},
extra y tick style={grid=major, dashed},
ytick={0,0.25,...,1},
ticklabel style={font=\footnotesize},
domain=0:360,
            ]
\addplot [red, thick, mark=none, samples=201] {0.5sin(x)+0.5};
\addplot [ycomb, red, samples=13,
          mark=, mark options={scale=0.75, fill=white}] {0.5*sin(x)+0.5};
\end{axis}
    \end{tikzpicture}
\end{document}
Zarko
  • 296,517