Question

wrote a code in mathlab to find the inverse of a matrix (5x5), USING CoFACTOR method. use numbers 1-15 as variables

Answer 1

Answer:-

Formula

We have to write script file to find out cofactor of matrix.

Script file:-

%-----------------------------------------------------------------------------------------------------------------------------

function cof=cof(a)

%% Check Input Argument
%----------------------
if isempty(a)
error(message('cof:EmptyMatrix'));
end
%% Algorithm
%-----------
[r, c] = size(a); %determine size of input   
m = ones(r,c); %preallocate r x c cofactor matrix
a_temp=a; %create temporary matrix equal to input
for i = 1:r
for k = 1:c
a_temp([i],:)=[]; %remove ith row
a_temp(:,[k])=[]; %remove kth row
m(i,k) = ((-1)^(i+k))*det(a_temp); %compute cofactor element
a_temp=a; %reset elements of temporary matrix to input elements
end
end
cof=m; %return cofactor matrix as output variable
end

%----------------------------------------------------------------------------------------------------------------------------

Paste above file in Editor section of matlab

(save it as name 'cof')

Then in command window type these command.(TYPE YOUR MATRIX AND INVERSE FORMULA given below)

Step 1.)  a=[1 2 5 4 8;7 5 8 9 6;4 1 4 5 2;7 8 5 6 3;7 8 5 2 1]

Step 2.) inverse=cof(a)'/det(a)

cof(a) command help us to find out cofactor of 'a' matrix.

det(a) command help us to find out Determent of 'a' matrix

cof(a)' Transpose of cofactor matrix

INVERSE formula using cofactor =  cof(a)'/det(a)

output:-

Editor Section

Command Window section :-

Full-screen shot of a working screen :-

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