摘要：程序文件ex8_8.py from scipy.integrate import odeint import numpy as np import pylab as plt yx = lambda y,x: [y[1], np.sqrt(1+y[1]**2)/5/(1-x)] x0 = np.ara 阅读全文

摘要：程序文件ex8_7.py from scipy.integrate import odeint import numpy as np import pylab as plt import sympy as sp dy = lambda y, x: -2y+2x2+2x #自变量在后面 xx = np 阅读全文

摘要：程序文件ex8_6.py import sympy as sp sp.var('t') sp.var('x1:4', cls=sp.Function) #定义3个符号函数 x = sp.Matrix([x1(t), x2(t), x3(t)]) #列向量 A = sp.Matrix([[3,-1,1 阅读全文

摘要：程序文件ex8_5.py import sympy as sp sp.var('t'); y=sp.Function('y') u=sp.exp(-t)sp.cos(t) eq=y(t).diff(t,4)+10y(t).diff(t,3)+35y(t).diff(t,2)+ 50y(t).diff 阅读全文

摘要：程序文件ex8_4.py import sympy as sp sp.var('x'); y=sp.Function('y') eq=y(x).diff(x,2)-2*y(x).diff(x)+y(x)-sp.exp(x) con={y(0): 1, y(x).diff(x).subs(x,0): 阅读全文

摘要：程序文件ex8_3.py import sympy as sp sp.var('x'); y=sp.Function('y') eq=y(x).diff(x)+2y(x)-2x**2-2*x s=sp.dsolve(eq, ics={y(0):1}) s=sp.simplify(s); print( 阅读全文