# ----------------------------------------------------------------------------- # Copyright (c) 2015, Nicolas P. Rougier. All Rights Reserved. # Distributed under the (new) BSD License. See LICENSE.txt for more info. # ----------------------------------------------------------------------------- import numpy as np import matplotlib.pyplot as plt plt.figure(figsize=(8,5), dpi=80) ax = plt.subplot(111) 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)) X = np.linspace(-np.pi, np.pi, 256,endpoint=True) C,S = np.cos(X), np.sin(X) plt.plot(X, C, color="blue", linewidth=2.5, linestyle="-", label="cosine") plt.plot(X, S, color="red", linewidth=2.5, linestyle="-", label="sine") plt.xlim(X.min()*1.1, X.max()*1.1) plt.xticks([-np.pi, -np.pi/2, 0, np.pi/2, np.pi], [r'$-\pi$', r'$-\pi/2$', r'$0$', r'$+\pi/2$', r'$+\pi$']) plt.ylim(C.min()*1.1,C.max()*1.1) plt.yticks([-1, +1], [r'$-1$', r'$+1$']) t = 2*np.pi/3 plt.plot([t,t],[0,np.cos(t)], color ='blue', linewidth=1.5, linestyle="--") plt.scatter([t,],[np.cos(t),], 50, color ='blue') plt.annotate(r'$\sin(\frac{2\pi}{3})=\frac{\sqrt{3}}{2}$', xy=(t, np.sin(t)), xycoords='data', xytext=(+10, +30), textcoords='offset points', fontsize=16, arrowprops=dict(arrowstyle="->", connectionstyle="arc3,rad=.2")) plt.plot([t,t],[0,np.sin(t)], color ='red', linewidth=1.5, linestyle="--") plt.scatter([t,],[np.sin(t),], 50, color ='red') plt.annotate(r'$\cos(\frac{2\pi}{3})=-\frac{1}{2}$', xy=(t, np.cos(t)), xycoords='data', xytext=(-90, -50), textcoords='offset points', fontsize=16, arrowprops=dict(arrowstyle="->", connectionstyle="arc3,rad=.2")) plt.legend(loc='upper left', frameon=False) plt.savefig("../figures/exercice_9.png",dpi=72) plt.show()