Need some help to solve differential equation with AdamsBDF solver

Hello,

Currently I have been facing some errors to solve differential equations using AdamsBDF solver.

Your kind help or advice will be very much appreciated.

Please see the belwo images and attached file for equations and the problem with "D"_Red Circle.

Thank you.

Best answer by Werner_E

When you defined D(t,X) you type a square bracket for the second entry and so you created inadvertently a 1x1 matrix .

Simply use 'normal' parentheses and its works:

BTW, there is no need to use a solve block when you use one of the stand alone ODE solvers. A solve block is needed only when you use 'odesolve'.

You may get a smoother result if you either increase N significantly or use a smaller interval [Ti; Tf], or both:

Answer

25-Diamond I

When you defined D(t,X) you type a square bracket for the second entry and so you created inadvertently a 1x1 matrix .

Simply use 'normal' parentheses and its works:

BTW, there is no need to use a solve block when you use one of the stand alone ODE solvers. A solve block is needed only when you use 'odesolve'.

You may get a smoother result if you either increase N significantly or use a smaller interval [Ti; Tf], or both:

25-Diamond I

In case you are interested, here is the system solved using a solve block with odesolve.

Prime 9 sheet attached

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