Cramer's Rule using for loop

Hi,

For a school exercise I need to use Cramer's rule to determine Ax=b.

I need to execute this using a for loop. Currently I'm facing an issue where if I replace the column's off A by, they will remain b so that my next determinant (x2) is not correct. How do I get the original (a1) column back in the second loop, (and again for the third en fourth)?

my current code:

A = [1,1,-3,2;0,-1,4,0;-3,1,2,2;1,2,3,6]
b = [1;2;3;4]
detA = det(A)
[z,z] = size(A); 
for g = 1:z;
  A(:,g) = b
   x = det(A)
end

Cheers,

Matthias

[Jan]

The current code has not relation to the Cramer's rule. Overwriting all values of A by b is not useful. Please check the definition of the Cramer's rule again and restart from scratch.

[Matthias Bossenbroek]

Dear Jan,

Thank you for your feedback. I am trying to applying the method used in the picture. Calculating all the determinants will be done after i fixed my current issue.

Kind regards, Matthias

[Anusha Sridharan]

[Answers Dev] Restored Edits

[Rakib Seemanto]

how to find the value of x and y by using Cramer’s rule from these equations:

𝑎𝑥+𝑏𝑦=𝑐 and 𝑑𝑥+𝑒𝑦=𝑓 ???

Answer 1

[KSSV]

A = rand(3) ;
b = rand(3,1) ;  
[m,n] = size(A) ;  
x = zeros(m,1) ;  
for i = 1:m
    T = A ;
    T(:,i) = b ;
    x(i) = det(T)/det(A) ;
end
% Simply use \
 sol = A\b ;
[x sol]

[Rakib Seemanto]

how to find the value of x and y by using Cramer’s rule from these equations:

𝑎𝑥+𝑏𝑦=𝑐 and 𝑑𝑥+𝑒𝑦=𝑓 ???