กราฟเส้นด้วย pgfplots

\begin{tikzpicture}
  \begin{axis}[xlabel=Week, ylabel=Orders, legend pos=north west]
    \addplot coordinates {(1,12) (2,18) (3,25) (4,31) (5,44)};
    \addplot coordinates {(1,10) (2,14) (3,15) (4,21) (5,24)};
    \addplot+[dashed] coordinates {(1,5) (2,9) (3,8) (4,12) (5,13)};
    \legend{Erika, Hans, John}
  \end{axis}
\end{tikzpicture}

\begin{tikzpicture}
  \begin{axis}[domain=0:4, samples=9, legend pos=outer north east]
    \addplot[blue, thick, mark=*] {x};
    \addplot[red, dashed, mark=square*, mark options={fill=white}] {x^1.5/2};
    \addplot[teal, densely dotted, very thick] {sqrt(x)};
    \addplot[orange, mark=triangle*, mark size=3pt, only marks] {4 - x};
    \legend{linear, power, root, falling}
  \end{axis}
\end{tikzpicture}

\begin{tikzpicture}
  \begin{axis}[cycle list name=black white, width=6.5cm, height=5cm, title={black white}]
    \addplot coordinates {(0,0) (1,1) (2,4)};
    \addplot coordinates {(0,1) (1,2) (2,2)};
    \addplot coordinates {(0,2) (1,0) (2,1)};
  \end{axis}
\end{tikzpicture}
\begin{tikzpicture}
  \begin{axis}[cycle list={{red, thick}, {blue, dashed}}, width=6.5cm, height=5cm, title={custom}]
    \addplot coordinates {(0,0) (1,1) (2,4)};
    \addplot coordinates {(0,1) (1,2) (2,2)};
  \end{axis}
\end{tikzpicture}

\begin{tikzpicture}
  \begin{axis}[ymin=0, legend pos=north west]
    \addplot+[smooth] coordinates {(0,1) (1,2.5) (2,1.8) (3,3.2) (4,2.4)};
    \addplot+[const plot] coordinates {(0,0.5) (1,1) (2,1.5) (3,1.2) (4,2)};
    \legend{smooth, const plot}
  \end{axis}
\end{tikzpicture}

\begin{tikzpicture}
  \begin{axis}[domain=0:2*pi, samples=80, xlabel=$t$,
               xtick={0,1.5708,3.1416,4.7124,6.2832},
               xticklabels={$0$,$\frac{\pi}{2}$,$\pi$,$\frac{3\pi}{2}$,$2\pi$},
               legend pos=south west]
    \addplot[blue, thick] {sin(deg(x))};
    \addplot[red, thick, dashed] {cos(deg(x))};
    \legend{$\sin t$, $\cos t$}
  \end{axis}
\end{tikzpicture}

\begin{tikzpicture}
  \begin{axis}[axis lines=middle, xmin=-1.3, xmax=1.3, ymin=-1.3, ymax=1.3]
    \addplot[purple, thick, domain=0:360, samples=120, variable=t]
      ({cos(t)}, {sin(2*t)});
  \end{axis}
\end{tikzpicture}

\begin{tikzpicture}
  \begin{axis}[ymin=-10, ymax=10, axis lines=middle]
    \addplot[blue, thick, domain=-3:3, samples=200,
             restrict y to domain=-10:10, unbounded coords=jump] {1/x};
  \end{axis}
\end{tikzpicture}