Plotting a random function f(x) and f(x)+sin(x) with tikz

Question

I'm plotting a function f(x) with random values as follows:

\documentclass[tikz]{standalone}

\begin{document}
\begin{tikzpicture}
\draw[color=blue, samples=150]  plot[domain=0:10] (\x,rand) node[below] {$f(x)$};
\end{tikzpicture}
\end{document}

Now I want to plot a new Function g(x) which is defined as g(x)=f(x)+sin(x). Is there a way to do that?

I would really appreciate any help.

Thanks

Welcome to TeX.SX! And thank you for providing a minimal working example (MWE)! — Mensch, Aug 05 '13 at 18:48
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Qrrbrbirlbel · Answer 1 · 2013-08-05T18:38:50.663

Yes, this is easily possible if you set the seed directly before the plot and use the same samples and domain settings.

If you don’t want to set the seed manually, you can store it before the first plot and re-set it afterwards.

Code

\documentclass[tikz,convert=false]{standalone}
\makeatletter
\def\pgfmathstoreseed#1{\let#1\pgfmath@rnd@z}
\let\pgfmathrestoreseed\pgfmathsetseed
\makeatother
\begin{document}
\begin{tikzpicture}
  \pgfmathstoreseed\mySeed
  \draw[color=blue, samples=250] plot[domain=0:10] (\x,rand/10) node[right] {$f(x)$};
  \pgfmathrestoreseed\mySeed
  \draw[color=red,  samples=250] plot[domain=0:10] ({\x,rand/10 + sin (\x r)})
                                                       node[below] {$f(x) + \sin x$};
\end{tikzpicture}

\begin{tikzpicture}
  \pgfmathsetseed{126838}
  \draw[color=blue, samples=250] plot[domain=0:10] (\x,rand/10) node[right] {$f(x)$};
  \pgfmathsetseed{126838}
  \draw[color=red,  samples=250] plot[domain=0:10] ({\x,rand/10 + sin (\x r)})
                                                       node[below] {$f(x) + \sin x$};
\end{tikzpicture}
\end{document}
\end{document}

Output

enter image description here

That is exactly what I was looking for. Thank you. – Staple Aug 05 '13 at 18:41 — Staple, Aug 05 '13 at 18:41

Plotting a random function f(x) and f(x)+sin(x) with tikz

1 Answers1

Code

Output

Linked