How can I use trigonometric functions and tick labels with pgfplots?

Question

\begin{tikzpicture}
\begin{axis}[
  axis lines=middle,
  samples=100,
  ymax=5,legend pos=north east,
  legend style={draw=none}
]
\addplot[forget plot,cyan,domain=0.001:8] {abs(log10(x))};
\addplot[forget plot,red!70!black,domain=-2:4] {2+exp(abs(x))};
\addplot[green,thick,domain=-2:3] {exp(x)};
\addlegendentry{$e^{x}$};
\node[pin={90:$f(x)=\lvert\log x\rvert$},inner sep=0pt] 
  at (axis cs:{2,log10(2)}) {};
\node[pin={0:$f(x)=e^{x}$},inner sep=0pt] 
  at (axis cs:{1,exp(1)}) {};
\node[anchor=north west] 
  at (axis description cs:0,0.5)
  {$\lvert e^{x}\rvert$};
\end{axis}
\end{tikzpicture}

I have used these code to generate the curves. It shown to me like:

But after making change in the function abs(log(x)) into sin(x), like in the following codes,

 \begin{tikzpicture}
\begin{axis}[
  axis lines=middle,
  samples=100,
  ymax=5,legend pos=north east,
  legend style={draw=none}
]
\addplot[forget plot,cyan,domain=0.001:8] {sin(x)};
\addplot[forget plot,red!70!black,domain=-2:4] {2+exp(abs(x))};
\addplot[green,thick,domain=-2:3] {exp(x)};
\addlegendentry{$e^{x}$};
\node[pin={90:$f(x)=\lvert\log x\rvert$},inner sep=0pt] 
  at (axis cs:{2,log10(2)}) {};
\node[pin={0:$f(x)=e^{x}$},inner sep=0pt] 
  at (axis cs:{1,exp(1)}) {};
\node[anchor=north west] 
  at (axis description cs:0,0.5)
  {$\lvert e^{x}\rvert$};
\end{axis}
\end{tikzpicture}

I got the image as

Requirements

(1) I should have my sin x graph with this graphs.

(2) My x-axis tick must have $-\pi, \frac \pi 2 ,...$ means I want radian measure ticks.

How do I do this.?

For 1): sin assumes degrees, use sin(deg(x)). For 2), see if Axis with trigonometric labels in PGFPlots, Graphing trigonometric functions, axes labeled with tick marks or Locating tick marks at integral multiples of pi/2 help. — Torbjørn T., Jul 28 '15 at 19:48
Also http://tex.stackexchange.com/questions/253738/trigonometric-tikz, although the other links may be better. However, this one includes an answer I wrote which includes references for relevant questions and for pages from the manual. Basically, it has these because I was figuring out how to do things more-or-less from scratch. So I thought the commented references might be helpful. — cfr, Jul 28 '15 at 22:00

Stefan Kottwitz · Accepted Answer · 2015-08-16T11:44:07.617

Besides fixing it by writing as sin(x), you can switch from degrees to radian with pgfplots 1.11 and newer:

\pgfplotsset{trig format plots=rad}

After adding it to your drawing, I got the sine function nicely displayed:

This was first mentioned on TeXwelt by the pgfplots author in an answer to "Kann man bei pgfplots die Argumente trigonometrischer Funktionen von Grad auf Radiant umstellen".

Furthermore, you could get radian in ticks by

  xtick = {-1.5707, 0, ..., 6.28318},
  xticklabels = {$-\frac{\pi}{2}$, 0, 
    $\frac{\pi}{2}$, $\pi$, $\frac{3\pi}{2}$, $2\pi$}

How can I use trigonometric functions and tick labels with pgfplots?

1 Answers1