#範例14-1：求線性系統的解(比較sympy模組，numpy模組的解法)
# -1x1+3x2+2x3 = 1
# x1+2x2-3x3 = -9
# 2x1+1x2-2x3 = -3
from sympy import *
x1,x2,x3 = symbols('x1 x2 x3')
M = Matrix([
    [-1,3,2,1],
    [1,2,-3,-9],
    [2,1,-2,-3]
    ])
    
ans = solve_linear_system(M, x1, x2, x3)
print('用sympy解聯立方程式 = ', ans)

import numpy as np
A = np.array([
    [-1,3,2],
    [1,2,-3],
    [2,1,-2]
    ])
Y = np.array([
    [1],[-9],[-3]
    ])
X = np.linalg.solve(A, Y)
print('用numpy解聯立方程式，X=\n', X)