Solving linear matrix equations

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Thank you for your reply! What kind of information do i need to specify? It's an angle, so do i have to declare it as a real?

Also, when i do solve(sys[0],psi_d)

it gives : TypeError: 'module' object has no attribute '__getitem__' what does it mean?

I'm not sure about that error. I'm assuming you did something like var('V_f, phi, V, L, psi_d') at the beginning of your work.

I've not been successful with getting the solving to work when the two nontrivial equations are both involved. Sage (actually Maxima) seems to be having some sort of issue with this case. It's got me baffled.

I think the problem is in sys[0], actually if i do show(sys[0]) it gives the same errore message. i tried writing

for i in range (0,3):

sys[i]=[ans1[i]==rV_fa[i]]

but it says TypeError: 'module' object does not support item assignment. What does it means?

How can I fix it? It seems a very simple operation to me but i can't understand what it is that I'm doing wrong.

I think you might have imported the python module sys at some point in your worksheet. In that case, you cannot use sys as a variable name. Try changing that variable name to something else and see if that resolves the error.

In addition, the code you suggested above will not assign things to sys[i] unless you initialize the sys variable as a list with 3 objects. This is the reason you are getting the error in this case.