@585 `y=\sin x`定义与图象

本帖最后由色k 于 2018-4-9 23:26 编辑

教学乡长

2018-4-9 23:22

我要画这个

\begin{tikzpicture}[scale=1.3]
\draw[->] (-2.5,0)--(6.7,0)node[below]{$x$};
\draw[->] (0,-1.5)--(0,1.5)node[left]{$y$};
\node[below left] at (0,0) {$O$};
\node[below right] at (0,-1) {$-1$};
\node[above right] at (0,1) {$1$};
\node[below] at (3.1416/2,0) {$\frac\pi2$};
\node[above right] at (3.1416,0) {$\pi$};
\node[above] at (3.1416*3/2,0) {$\frac{3\pi}2$};
\node[above] at (3.1416*2,0) {$2\pi$};
\draw[domain=0:2*3.1416,smooth] plot (\x,{sin(\x r)});
\node at (4.5,1.3) {$y=\sin x$, $x\in[0,2\pi]$};
\coordinate (O1) at (-1.5,0);
\draw (O1) circle (1);
\node[below right] at (O1) {$O_1$};
%%下面才是重点
\foreach \i in {0,...,11} {
  \coordinate (A\i) at ({cos(\i*30)-1.5},{sin(\i*30)});
  \coordinate (B\i) at (\i*3.1416/6,{sin(\i*30)});
  \draw (O1)--(A\i);
  \draw[dashed] (A\i)--(A\i|-0,0);
  \draw[dashed] (B\i)--(B\i|-0,0);
}
\foreach \i in {3,4,5} \draw[dashed] (A\i)--(B\i);
\draw[dashed] (A7)--(B11);
\draw[dashed] (A8)--(B10);
\draw[dashed] (A9)--(B9);
\node[above right] at (A0) {$A$};
\node[above] at (A3) {$B$};
\node[above] at (B3) {$(B)$};
\end{tikzpicture}