@585 `y=\sin x`定义与图象

色k

教学乡长

我要画这个

1. \begin{tikzpicture}[scale=1.3]
2. \draw[->] (-2.5,0)--(6.7,0)node[below]{$x$};
3. \draw[->] (0,-1.5)--(0,1.5)node[left]{$y$};
4. \node[below left] at (0,0) {$O$};
5. \node[below right] at (0,-1) {$-1$};
6. \node[above right] at (0,1) {$1$};
7. \node[below] at (3.1416/2,0) {$\frac\pi2$};
8. \node[above right] at (3.1416,0) {$\pi$};
9. \node[above] at (3.1416*3/2,0) {$\frac{3\pi}2$};
10. \node[above] at (3.1416*2,0) {$2\pi$};
11. \draw[domain=0:2*3.1416,smooth] plot (\x,{sin(\x r)});
12. \node at (4.5,1.3) {$y=\sin x$, $x\in[0,2\pi]$};
13. \coordinate (O1) at (-1.5,0);
14. \draw (O1) circle (1);
15. \node[below right] at (O1) {$O_1$};
16. %%下面才是重点
17. \foreach \i in {0,...,11} {
18.   \coordinate (A\i) at ({cos(\i*30)-1.5},{sin(\i*30)});
19.   \coordinate (B\i) at (\i*3.1416/6,{sin(\i*30)});
20.   \draw (O1)--(A\i);
21.   \draw[dashed] (A\i)--(A\i|-0,0);
22.   \draw[dashed] (B\i)--(B\i|-0,0);
23. }
24. \foreach \i in {3,4,5} \draw[dashed] (A\i)--(B\i);
25. \draw[dashed] (A7)--(B11);
26. \draw[dashed] (A8)--(B10);
27. \draw[dashed] (A9)--(B9);
28. \node[above right] at (A0) {$A$};
29. \node[above] at (A3) {$B$};
30. \node[above] at (B3) {$(B)$};
31. \end{tikzpicture}

复制代码

isee

回复 1# 色k

"偷"走了，虽然，基本都是直接用GSP演示

kuing

教学乡长 12:50:37
  \draw[dashed] (A\i)--(A\i|-0,0)
后面那个是怎么回事

设 A(x1,y1), B(x2,y2)，则 (A|-B)=(x1,y2), (A-|B)=(x2,y1)
一图胜千言：

isee

回复 3# kuing


如果是完全没用过tikz（或者其它命令式）画图的，解释起来是相当困难的

kuing

无意中看了下这帖，才发现原来原图的正弦线是紫色的……

Tesla35

回复 5# kuing

擦……