def rot_matrix(theta):
    '\n    rot_matrix(theta)\n    2D rotation matrix for theta in radians\n    returns numpy matrix\n    '
    (c, s) = (np.cos(theta), np.sin(theta))
    return np.matrix([[c, (- s)], [s, c]])
rot_matrix(theta)
2D rotation matrix for theta in radians
returns numpy matrix
def rot_matrix(theta):
    '\n    rot_matrix(theta)\n    2D rotation matrix for theta in radians\n    returns numpy matrix\n    '
    (c, s) = (np.cos(theta), np.sin(theta))
    return np.matrix([[c, (- s)], [s, c]])