# 3D-vectorveld import matplotlib.pyplot as plt import numpy as np x, y, z = np.meshgrid (np.arange (-1, 1, 0.25), np.arange (-1, 1, 0.25), np.arange (-1, 1, 0.25)) u = 2 * x / np.sqrt (x**2 + y**2) v = 2 * y / np.sqrt (x**2 + y**2) w = 1 plt.figure (figsize = (8, 8)) ax = plt.axes (projection = "3d") q = ax.quiver (x, y, z, u, v, w, color = "purple", length = 0.15) plt.show ()