Math = Symbol + Logic: 2017/11

#題目：作 y=|sin(x)+0.5| 的函數圖形

#Python 程式碼如下

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)

Sin_y = np.sin(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, abs(Sin_y+0.5), color="red", linewidth=3.0, linestyle="-", label="y=|sin(x)+0.5|")

# 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:
# 作 y=|sin(x)+0.5| 的函數圖形
