# -*- coding: utf-8 -*
# 在Python2.7下可运行
# 求解非线性方程组 2*x1-x2^2 = 1, x1^2-x2 = 2
from scipy.optimize import fsolve
def f(x):
    x1 = x[0]
    x2 = x[1]
    return [2*x1 - x2**2 -1, x1**2 - x2 -2]
result = fsolve(f, [1,1])
print(result)

#数值积分
from scipy import integrate
def g(x):
    return (1-x**2)**0.5

pi_2, err = integrate.quad(g, -1, 1)
print(pi_2 * 2)
