确认笛卡尔坐标(-1.34,2.68)对应的向量的长度约为3\n\nEXERCISE: Confir

def solve():
    import matplotlib.pyplot as plt
    import numpy as np
    from math import sqrt
    
    v = (-1.34, 2.68)
    length_v = sqrt(v[0]**2 + v[1]**2)
    
    plt.figure(figsize=(8, 6))
    plt.quiver(0, 0, v[0], v[1], angles='xy', scale_units='xy', scale=1, color='blue', 
               label=f'v = ({v[0]}, {v[1]}), |v| ≈ {length_v:.2f}')
    
    circle = plt.Circle((0, 0), length_v, fill=False, color='red', linestyle='--', label=f'半径 = {length_v:.2f}')
    plt.gca().add_patch(circle)
    
    plt.xlim(-4, 4)
    plt.ylim(-1, 4)
    plt.axhline(y=0, color='k', linewidth=0.5)
    plt.axvline(x=0, color='k', linewidth=0.5)
    plt.grid(alpha=0.3)
    plt.legend()
    plt.title('向量长度验证')
    plt.xlabel('x')
    plt.ylabel('y')
    plt.axis('equal')
    plt.tight_layout()
    plt.show()
    
    print(f"向量长度 = {length_v:.4f}")