# What is wrong with: [betta;del​ta;gamma]=​inv([ab ab_cd -cd])*[C-A];

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mb12345 on 25 Oct 2018
Edited: John D'Errico on 30 Oct 2018
Hi
[betta;delta;gamma]=inv([ab ab_cd -cd])*[C-A];
betta, delta and gamma should be scalars.
ab, ab_cd, cd, C and A are column vectors with 3 rows (e.g. [1;2;3]).
I want that
betta = leftvektor(1)
delta = leftvektor(2)
gamma = leftvektor(3)
Matlab shows an error but I am not sure why. Does anyone knows why?

Bruno Luong on 30 Oct 2018
Edited: Bruno Luong on 30 Oct 2018
You cannot capture elements of array on the lhs directly to variables, you have to split it:
x = inv([ab ab_cd -cd])*[C-A];
betta = x(1); % beta is better me think
delta = x(2);
gamma = x(3);

John D'Errico on 30 Oct 2018
Edited: John D'Errico on 30 Oct 2018
Why? This is because what you want to do is not valid in MATLAB. You can want for anything. If wishes were horses, beggars would ride.
You cannot split a result as a vector into multiple arguments.
Can you solve the problem? Well, yes. Sigh. Write a little helper function that will take a vector, and automatically split it into scalars.
function varargout = split2scalars(Vec)
% splits a vector of length n into n scalars
n = numel(Vec);
varargout = mat2cell(Vec(:),ones(n,1),1);
So ...
[Vx,Vy,Vz] = split2scalars(1:3)
Vx =
1
Vy =
2
Vz =
3
Use it as:
[betta;delta;gamma] = split2scalars(inv([ab ab_cd -cd])*[C-A]);