import numpy as np import matplotlib.pyplot as plt import random def vector_3d(ax, s_p, vec, color = "red", length = 1, arrow_length_ratio=0.05): ax.quiver(s_p[0], s_p[1], s_p[2], vec[0], vec[1], vec[2], color = color, length = length, arrow_length_ratio=arrow_length_ratio) def descartes_3d(ax, ran_x, ran_y, ran_z, ax_title, x_label = "x", y_label = "y", z_label="z"): ax.set_xlabel(x_label, fontsize = 12) ax.set_ylabel(y_label, fontsize = 12) ax.set_zlabel(z_label, fontsize = 12) ax.set_xlim(ran_x[0], ran_x[1]) ax.set_ylim(ran_y[0], ran_y[1]) ax.set_zlim(ran_z[0], ran_z[1]) ax.set_title(ax_title, fontsize = 16) ax.grid() fig = plt.figure(figsize = (10, 10)) ax = fig.add_subplot(111, projection='3d') title1 = "Kyoto University 2024 Math qu.3 NO1_2" descartes_3d(ax, [-1, 3], [-1, 3], [-1, 3], title1) point_O = np.array([0, 0, 0]) point_A = np.array([2, 0, 0]) point_B = np.array([2,2,2]) point_C = np.array([0,2,0]) point_P = np.array([1,0,0]) point_Q = np.array([2,1,1]) ax.text(0,0,0,"O",fontsize="xx-large") ax.text(2,0,0,"A",fontsize="xx-large") ax.text(2,2,2,"B",fontsize="xx-large") ax.text(0,2,0,"C",fontsize="xx-large") ax.text(1,0,0,"P",fontsize="xx-large") ax.text(2,1,1,"Q",fontsize="xx-large") vector_3d(ax, point_O, point_A, "red",1,0.05) vector_3d(ax, point_O, point_B, "red",1,0.05) vector_3d(ax, point_O, point_C, "red",1,0.05) vector_3d(ax, point_A, point_B-point_A, "red",1,0.05) n=20 dd=2.5 for x in np.linspace(0,1,n): for y in np.linspace(0,1,n): if x == y: point_X=x*point_C point_Y=(1-y)*point_B+y*point_C r=random.random() g=random.random() b=random.random() vector_3d(ax,point_Q,point_Y-point_Q,color=(r,g,b),length=dd) vector_3d(ax,point_P,point_X-point_P,color=(r,g,b),length=dd) plt.show()