ex8.7

合集 - 第八章作业加例题(14)

1.习题8.42024-11-122.习题8.52024-11-123.ex8.32024-11-124.ex8.42024-11-125.ex8.52024-11-126.ex8.62024-11-12

7.ex8.72024-11-12

8.ex8.82024-11-129.ex8.92024-11-1210.ex8.102024-11-1211.ex8.112024-11-1212.ex8.122024-11-1213.习题8.92024-11-1914.习题8.82024-11-21

收起

from scipy.integrate import odeint
import numpy as np
import pylab as plt
import sympy as sp

dy = lambda y, x: -2*y+2*x**2+2*x  #自变量在后面
xx = np.linspace(0,3,31)
s = odeint(dy, 1, xx)
print('x={}\n对应的数值解y={}'.format(xx, s.flatten()))
plt.plot(xx, s,'*')
sp.var('x'); y=sp.Function('y')
eq=y(x).diff(x)+2*y(x)-2*x**2-2*x
s=sp.dsolve(eq,ics={y(0):1})
sx = sp.lambdify(x,s.args[1],'numpy')  #符号函数转匿名函数
plt.plot(xx, sx(xx))
plt.show()