Symbolically solving vectors simultaneously

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Ramses Young
Ramses Young 2022-4-30
评论： Star Strider 2022-5-1
Hello, I have been trying to solve a vector using the symbolic toolbox and am running into an error that says "Error using maplemex
Error, (in MTM:-solve) 0 variables do not match undefined outputs.", I am currently trying to solve for a variable in a matrix that is equal to zero, below is an example.
syms q0
moment=[5*q0+25 6*q0+45 5*q0+45]
[q0]=solve(moment==0)
This specific example is solving moment equilibrium for a monocoque structure.
Is there a way to solve the seperate q0 values so its a vector like [q0_1 q0_2 q0_3] using the symbolic toolbox?
Thanks!!!

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采纳的回答

Star Strider
Star Strider 2022-4-30
Ran in:
One solve statement (such as in the original post) also fails in R2022a. One option to get all of the solutions is arrayfun that should be available (another is an explicit loop) —
syms q0
moment = [5*q0+25 6*q0+45 5*q0+45];
q0 = arrayfun(@(x)solve(x), moment)
q0 = 
.
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Ramses Young
Ramses Young 2022-5-1
I decided to completely uninstall maple and reinstall all the matlab toolboxes and these to have fixed all the maple stuff that was causing issues. Kinda annoying that Maple makes the matlab stuff not work correctly. But thank you all for the help!
Star Strider
Star Strider 2022-5-1
As always, my pleasure! (And thanks to Walter for his observations.)

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更多回答（1 个）

Paul
Paul 2022-4-30
Ran in:
q0 = sym('q0_',[1 3])
q0 = 
moment=[5*q0(1)+25 6*q0(2)+45 5*q0(3)+45]
moment = 
solve(moment==0,q0)
ans = struct with fields:
q0_1: -5 q0_2: -15/2 q0_3: -9
  2 个评论
Walter Roberson
Walter Roberson 2022-4-30
I do not recall whether the interface to maple supports using sym that way to create a vector. Maybe?
Ramses Young
Ramses Young 2022-4-30
This didnt work for me, It is giving me the same error I put in the post... is there a way to go around this??
Thanks!

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