首先，我试着计算一个平面，这个平面适合三维空间中的一组点，我已经用下面的代码完成了这个计算：

import numpy as np
import scipy.linalg

# Create some 3-dim points

mean = np.array([0.0,0.0,0.0])
cov = np.array([[1.0,-0.5,0.8], [-0.5,1.1,0.0], [0.8,0.0,1.0]])
data = np.random.multivariate_normal(mean, cov, 50)

# Fit plane

C,_,_,_ = scipy.linalg.lstsq(np.c_[data[:,0], data[:,1], np.ones(data.shape[0])], data[:,2])

# Coefficients in the form: a*x + b*y + c*z + d = 0.

a, b, c, d = C[0], C[1], -1., C[2]

但是一旦我有了平面的系数，我怎么才能知道平面与垂直线的夹角呢？谢谢！