如何使用函数及其导数（＆＃x27; s）在Python中求解另一个微分方程？

发布于 2025-01-24 06:19:18 字数 888 浏览 0 评论 0原文

我需要在Python中同时解决这两个方程式： “ B”是恒定的；但是我不知道如何将函数“ P”及其导数放在第二个方程式中，有人可以帮助我吗？

版：我已经写了此代码来解决这个问题，但我不知道它是正确的。此代码是否正确给出了这些方程式的答案？

import numpy as np
from scipy.integrate import odeint
import matplotlib.pyplot as plt
import scipy.integrate as sy
import sys
import numpy as np
np.set_printoptions(threshold=sys.maxsize)
import numpy as np
from scipy.integrate import solve_ivp
import matplotlib.pyplot as plt
b=2
def eq(t,u):
    #u[0] is p and u[1] is p', u[2]=y, u[3]=y'.
    u[1]=u[0]*np.sqrt(0.25*(u[0]**-4)*(u[0]+(1/7)+0.7)
    return [u[0],u[1],u[3],-3*(u[1]/(b*u[0]))*u[3] - u[2]]
u0 = [0.00001,0.00001,1.22*(10**28),0]
t = np.linspace(0.0000000001,0.6924*10**33,10000)
sol=solve_ivp(eq,t,u0,None)

原文

I need to solve this two equations simultaneously in python :

"b" is constant; but I don't know how to put the function "P" and its derivative at same time in the second equations code,
is there anyone could help me?

edition:
I have wrote this code to solve the question, but I don't know it is correct or not. is this code correctly gives the answer of those equations?

import numpy as np
from scipy.integrate import odeint
import matplotlib.pyplot as plt
import scipy.integrate as sy
import sys
import numpy as np
np.set_printoptions(threshold=sys.maxsize)
import numpy as np
from scipy.integrate import solve_ivp
import matplotlib.pyplot as plt
b=2
def eq(t,u):
    #u[0] is p and u[1] is p', u[2]=y, u[3]=y'.
    u[1]=u[0]*np.sqrt(0.25*(u[0]**-4)*(u[0]+(1/7)+0.7)
    return [u[0],u[1],u[3],-3*(u[1]/(b*u[0]))*u[3] - u[2]]
u0 = [0.00001,0.00001,1.22*(10**28),0]
t = np.linspace(0.0000000001,0.6924*10**33,10000)
sol=solve_ivp(eq,t,u0,None)

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