Graphics, Figures & Tables ⇒ Sine Curve with variable Amplitude

[fruitfrisje]

I'm trying to create an irregular sine curve that looks likes variable amplitude stress. I've tried the following code. It looks OK, but the shape of the curve is not fluent but it has sharp edges. Any one an idea?

Code: Select all

\documentclass[11pt,a4paper,twoside]{report}
\usepackage{tikz}
\usepackage{pgfplots}

\begin{document}
  \begin{tikzpicture}[scale=2]
    \draw [draw=black,thick,->] (0.00,0.00) -- (pi,0.00);	% draw x-axis bottom
    \draw [draw=black,thick,->] (0.00,-2.00) -- (0.00,2.00);	% draw y-axis bottom
    \draw [blue,domain=0:2*pi] plot (\x,{cos(\x*3 r)+0.5*sin(\x r)+sin(\x*0.5 r)});		
  \end{tikzpicture}
\end{document}

[mas]

Since you are already familiar with TikZ, use pgfplots to plot the graphs. It gives you more flexibility and features with plotting data and functions. Here is your reworked sample.

Code: Select all

\documentclass{standalone}
\usepackage{tikz}
\usepackage{pgfplots}

\begin{document}
  \begin{tikzpicture}
    \begin{axis}
      \addplot [samples=200,smooth,no markers] {cos(deg(3*x))+0.5*sin(deg(x))+sin(deg(0.5*x))} ;
    \end{axis}
  \end{tikzpicture}
\end{document}

[fruitfrisje]

That works perfectly!

But now I am not being able to change the axis dimensions. The plot only goes to about 5 (x-axis) but I would like it to go to 8.

Code: Select all

\documentclass[11pt,a4paper,twoside]{report}
\usepackage{pgfplots}

\begin{document}
  \begin{tikzpicture}
    \begin{axis}[
      xlabel=$N$,
      ylabel=$\Delta\sigma$,
      xmin=0,
      xmax=8,
%     ymin=-3,
%     ymax=3
    ]
      \addplot [samples=100,smooth,no markers,domain=0:7] {cos(deg(3*x))+0.5*sin(deg(x))+sin(deg(0.5*x))} ;
    \end{axis}
  \end{tikzpicture}
\end{document}

Edit: Nevermind, adding domain=0:7 did the trick (see code anove).