How to plot f(x)=sin(x), k(x)=cos(x) and u(x)=x² with TikZ

Question

How can we plot the following three functions

f(x) = sin(x)
k(x) = cos(x)
u(x) = x²

for x ∈ [0,1]

on a single plot with the help of TikZ?

Since you have some responses below that seem to answer your question, please consider marking one of them as ‘Accepted’ by clicking on the tickmark below their vote count (see How do you accept an answer?). This shows which answer helped you most, and it assigns reputation points to the author of the answer (and to you!). It's part of this site's idea to identify good questions and answers through upvotes and acceptance of answers. — Tobi, Aug 20 '13 at 16:12
See also: Incorrect plot using pgfplots (trigonometric functions like cos, sin and tan) - TeX - LaTeX Stack Exchange for trig format plots key etc.. — user202729, Oct 14 '22 at 01:41

score 38 · Answer 1 · edited May 29 '12 at 20:24

In pgfplots, you can implement the task with

\documentclass{article}
\usepackage{pgfplots}

\begin{document}
\begin{tikzpicture}
    \begin{axis}[domain=0:1,legend pos=outer north east]
    \addplot {sin(deg(x))}; 
    \addplot {cos(deg(x))}; 
    \addplot {x^2};
    \legend{$\sin(x)$,$\cos(x)$,$x^2$}
    \end{axis}
\end{tikzpicture}
\end{document}

Since the options are provided for the complete axis, the domain is shared among all these functions. The TikZ function deg(x) converts x from radians to degrees (similar to the postfix operator x r which does not appear to work in pgfplots).

The \legend describes the legend's values and the legend pos option is one of the prescribed ways to configure the legend.

enter image description here

You could also use \addplot[color=red] to configure color/marker and what-ever styles as discussed by Tobi.

Thanks for your addition! I was too lazy to give a full solution, but only because Mozo was too lazy to read the manual first himself … — Tobi, Apr 20 '11 at 21:43

score 17 · Answer 2 · answered Apr 20 '11 at 10:15

This is the example which can be fount in the pgfmanual.pdf on p. 225

\documentclass{minimal}
\usepackage{tikz,pgfplots}

\begin{document}
\begin{tikzpicture}[domain=0:4]
    \draw[very thin,color=gray] (-0.1,-1.1) grid (3.9,3.9);
    \draw[->] (-0.2,0) -- (4.2,0) node[right] {$x$};
    \draw[->] (0,-1.2) -- (0,4.2) node[above] {$f(x)$};
    \draw[color=red]    plot (\x,\x)    node[right] {$f(x) =x$};
    \draw[color=blue]   plot (\x,{sin(\x r)})   node[right] {$f(x) = \sin x$};
    \draw[color=orange] plot (\x,{0.05*exp(\x)}) node[right]
        {$f(x) = \frac{1}{20} \mathrm e^x$};
\end{tikzpicture}
\end{document}

Think you can adapt it for your functions?!

There ist also a way with pgfplots. See the above mentioned manual for more information.

Hi, what does r do in sin(\x r)? – The Imp Oct 15 '22 at 06:07 — The Imp, Oct 15 '22 at 06:07
@The Imp r stands for radian (instead of degree) – user4624500 Oct 16 '22 at 13:49 — user4624500, Oct 16 '22 at 13:49

How to plot f(x)=sin(x), k(x)=cos(x) and u(x)=x² with TikZ

2 Answers2

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