2022年5月10日 星期二

Euler's Formula

 Euler's Formula

2022/01/19

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https://pixabay.com/zh/illustrations/pay-numbers-infinity-digits-937884/

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◎ 說明:

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Fig. 1. Euler's Formula and Euler's identity [3].

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Fig. 2. Euler's Formula [3].

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整數次方是整數倍數的膨脹。開根號是整數倍數的收縮。i 次方是將實數在複數平面上逆時針旋轉 90 度 [4]。

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Euler's Formula:複數平面上的單位圓。

Euler's identity:在 180 度的地方值為 -1。

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Fig. 4. 歐拉公式的螺旋線呈現 [8]。

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代碼一:

import numpy as np
import matplotlib.pyplot as plt
from mpl_toolkits.mplot3d import Axes3D

n = 1000 # points of the helix
fig = plt.figure(figsize=(16,16))
ax = fig.add_subplot(111, projection='3d')

# Plot a helix along the x-axis (e.g. time)
theta_max = 6 * np.pi # number of the semicircle
theta = np.linspace(0, theta_max, n)
x = theta
z =  np.sin(theta)
y =  np.cos(theta)
ax.plot(x, y, z, 'r', lw=2)

# An line through the centre of the helix
ax.plot((-theta_max*0.2, theta_max * 1.2), (0,0), (0,0), color='k', lw=2)
# sin/cos components of the helix (e.g. phase and amplitude
# components of a circularly-polarized Eular's Formula
ax.plot(x, y, 0, color='b', lw=1, alpha=0.5)
ax.plot(x, [0]*n, z, color='m', lw=1, alpha=0.5)

# Remove axis planes, ticks and labels
ax.set_axis_off()

# plt.savefig('/content/drive/My Drive/helix.png')
# plt.show()

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◎ 參考資料:

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References

[1] Euler's formula - Wikipedia

https://en.wikipedia.org/wiki/Euler%27s_formula


[2] 歐拉公式 - 維基百科,自由的百科全書

https://zh.wikipedia.org/wiki/%E6%AC%A7%E6%8B%89%E5%85%AC%E5%BC%8F


[3] Deriving the famous Euler’s formula through Taylor Series – Muthukrishnan

https://muthu.co/deriving-the-famous-eulers-formula-through-taylor-series/


# 179 萬次觀看。縮放、旋轉。

[4] Euler's formula with introductory group theory - YouTube

https://www.youtube.com/watch?v=mvmuCPvRoWQ


# 級數方式呈現。

[5] What is Euler's formula actually saying? | Ep. 4 Lockdown live math - YouTube

https://www.youtube.com/watch?v=ZxYOEwM6Wbk


[6] 歐拉恆等式──最優美的數學定理 | 線代啟示錄

https://ccjou.wordpress.com/2012/05/11/%E6%AD%90%E6%8B%89%E6%81%86%E7%AD%89%E5%BC%8F-%E6%9C%80%E5%84%AA%E7%BE%8E%E7%9A%84%E6%95%B8%E5%AD%B8%E5%AE%9A%E7%90%86/


# 歐拉公式為何是一個複數平面上的圓

[7] e^(iπ) in 3.14 minutes, using dynamics | DE5 - YouTube

https://www.youtube.com/watch?v=v0YEaeIClKY


# 3D 螺旋線。可用來示範歐拉公式

[ 8] Depicting a helix

https://scipython.com/book/chapter-7-matplotlib/examples/depicting-a-helix/

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