#題目：分別作 y=sin(x) , y=cos(x) , y=tan(x) 的函數圖形
#Python 程式碼如下
# -*- coding: utf-8 -*-
import numpy as np
import matplotlib.pyplot as plt
# 產生x座標的資料，從 -2PI 到 2PI
X = np.linspace(-2*np.pi, 2*np.pi, 1000, endpoint=True)
# Y座標
Sin_y = np.sin(X)
Cos_y = np.cos(X)
Tan_y = np.tan(X)
plt.figure(figsize=(12,9),dpi=80)
ax = plt.gca() # gca stands for 'get current axis'
ax.spines['right'].set_color('none')
ax.spines['top'].set_color('none')
ax.xaxis.set_ticks_position('bottom')
ax.spines['bottom'].set_position(('data',0))
ax.yaxis.set_ticks_position('left')
ax.spines['left'].set_position(('data',0))
plt.plot(X, Sin_y, color="red", linewidth=1.0, linestyle="-", label="Sin")
plt.plot(X, Cos_y, color="green", linewidth=1.0, linestyle="-", label="Cos")
plt.plot(X, Tan_y, color="blue", linewidth=1.0, linestyle=":", label="Tan")
# 設定 y 座標範圍
plt.ylim(-2.0, 2.0)
# 設定 x 座標文字
plt.xticks([-2*np.pi, -3*np.pi/2,-np.pi, -np.pi/2, 0, np.pi/2, np.pi, 3*np.pi/2,2*np.pi],
[r'$-2\pi$', r'$-3\pi/2$',r'$-\pi$', r'$-\pi/2$', r'$0$', r'$+\pi/2$', r'$+\pi$', r'$3\pi/2$',r'$2\pi$'])
plt.legend(loc='upper left')
plt.show()
# 輸出結果如下:
