Solving coupled ODEs via ode45

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Seymen 2024-3-2

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https://ww2.mathworks.cn/matlabcentral/answers/2089456-solving-coupled-odes-via-ode45

回答： Sulaymon Eshkabilov 2024-3-3

Hello,

I have 2 secound order and coupled ordinary differential equations. For the first equation, I could find an explicit solution, i.e. d^2y/dt^2=.....

However, for the second equation, I could not find an explicit solution. Therefore, I couldn't use ode45 etc. How can I solve these equations numerically?

Thank you in advance

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Torsten 2024-3-2

在 MATLAB Online 中打开

ode45 can solve first-order initial value problems. Thus your equations must be of the form dy/dt = f(t,y).

If you have a second-order differential equation

d^2y/dt^2 = g(t,y,dy/dt)

, it can be written as two first-order differential equations by putting

z(1) = y, z(2) = dy/dt

The system then reads

dz(1)/dt = z(2)
dz(2)/dt = g(t,z(1),z(2))

Steven Lord 2024-3-2

Can you show us the form of the differential equations that you do know? If you show us the mathematical equations we may be able to help you translate them into MATLAB code.

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