I keep getting the error message that the variables must be of data type double and it is currently of type sym.

Question

Ana 2024-2-21

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/2085088-i-keep-getting-the-error-message-that-the-variables-must-be-of-data-type-double-and-it-is-currently

评论： Ana 2024-2-21

采纳的回答： Walter Roberson

在 MATLAB Online 中打开

%I'm unsure how else to run this code to solve the 10 eqn system where

%the answer comes out in the correct form, please help

syms AB BC AD BD CD DE CE Ax Ay Ey

eqn1=Ax+AD==0;

eqn2=Ay+AB==0;

eqn3=74+BC+(3/5)*BD==0;

eqn4=-AB-(4/5)*BD==0;

eqn5=-BC+(3/5)*CE==0;

eqn6=-24-CD-(4/5)*CE==0;

eqn7=-AD+DE-(3/5)*BD==0;

eqn8=CD+(4/5)*BD==0;

eqn9=-DE-(3/5)*CE==0;

eqn10=Ey+(4/5)*CE==0;

[AB BC AD BD CD DE CE Ax Ay Ey]=solve(eqn1, eqn2, eqn3, eqn4, eqn5, eqn6, eqn7, eqn8, eqn9, eqn10,[AB BC AD BD CD DE CE Ax Ay Ey])

AB =

BC =

AD =

74

BD =

CD =

DE =

46

CE =

Ax =

Ay =

Ey =

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Walter Roberson 2024-2-21

编辑：Walter Roberson 2024-2-21

在 MATLAB Online 中打开

The code works properly here.

Try

restoredefaultpath; rehash toolboxcache

Ana 2024-2-21

it is still giving me these error messages

"Variable AB must be of data type double. It is currently of type sym. Check where the variable is assigned a value."

is it because I introduce them using 'syms', it also said i cannot use rehash in my code on Matlab Grader

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Answer 1

Walter Roberson 2024-2-21

1
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/2085088-i-keep-getting-the-error-message-that-the-variables-must-be-of-data-type-double-and-it-is-currently#answer_1413903

在 MATLAB Online 中打开

%I'm unsure how else to run this code to solve the 10 eqn system where
%the answer comes out in the correct form, please help
syms AB BC AD BD CD DE CE Ax Ay Ey
eqn1=Ax+AD==0;
eqn2=Ay+AB==0;
eqn3=74+BC+(3/5)*BD==0;
eqn4=-AB-(4/5)*BD==0;
eqn5=-BC+(3/5)*CE==0;
eqn6=-24-CD-(4/5)*CE==0;
eqn7=-AD+DE-(3/5)*BD==0;
eqn8=CD+(4/5)*BD==0;
eqn9=-DE-(3/5)*CE==0;
eqn10=Ey+(4/5)*CE==0;
[AB BC AD BD CD DE CE Ax Ay Ey]=solve(eqn1, eqn2, eqn3, eqn4, eqn5, eqn6, eqn7, eqn8, eqn9, eqn10,[AB BC AD BD CD DE CE Ax Ay Ey]);
AB = double(AB);
BC = double(BC);
AD = double(AD);
BD = double(BD);
DE = double(DE);
CE = double(CE);
Ax = double(Ax);
Ay = double(Ay);
Ey = double(Ey);