# how can we perform 6x6 matrix without values to find the inverse and determination

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prabakaran Rajendiran on 11 Jun 2019
to create a 6x6 matrix and find the inverse and determination of the above matrix without any values
x=[a(1,1) a(1,2) a(1,3) a(1,4) a(1,5) a(1,6);
a(2,1) a(2,2) a(2,3) a(2,4) a(2,5) a(2,6);
a(3,1) a(3,2) a(3,3) a(3,4) a(3,5) a(3,6);
a(4,1) a(4,2) a(4,3) a(4,4) a(4,5) a(4,6);
a(5,1) a(5,2) a(5,3) a(5,4) a(5,5) a(5,6);
a(6,1) a(6,2) a(6,3) a(6,4) a(6,5) a(6,6)]
to find
| X | = ?
X-inv = 1/| X | (adj X)

Mohammad Alhashash on 11 Jun 2019
You can do that using the Symbolic Math Toolbox. And you can check wether you have this toolbox or not using the simple command :
ver
If you do have it, then you have to define the arguements a(i,j) in slightly different manner using the underscore characters instead of comma, i.e. :
syms a_1_1 a_1_2 a_1_3 a_1_4 a_1_5 a_1_6
syms a_2_1 a_2_2 a_2_3 a_2_4 a_2_5 a_2_6
syms a_3_1 a_3_2 a_3_3 a_3_4 a_3_5 a_3_6
syms a_4_1 a_4_2 a_4_3 a_4_4 a_4_5 a_4_6
syms a_5_1 a_5_2 a_5_3 a_5_4 a_5_5 a_5_6
syms a_6_1 a_6_2 a_6_3 a_6_4 a_6_5 a_6_6
then redefine our matrix X using these arguements:
X = [a_1_1 a_1_2 a_1_3 a_1_4 a_1_5 a_1_6;...
a_2_1 a_2_2 a_2_3 a_2_4 a_2_5 a_2_6;...
a_3_1 a_3_2 a_3_3 a_3_4 a_3_5 a_3_6;...
a_4_1 a_4_2 a_4_3 a_4_4 a_4_5 a_4_6;...
a_5_1 a_5_2 a_5_3 a_5_4 a_5_5 a_5_6;...
a_6_1 a_6_2 a_6_3 a_6_4 a_6_5 a_6_6]
Then simply use the inv and det commands to determine what you seek for:
X_det = det(X);
X_inv = inv(X);
Keep in mind that the inverse answer will be very long and may extened beyond the matlab command window allowable space.
prabakaran Rajendiran on 11 Jun 2019
my college have full suite with 50 license

Manvi Goel on 11 Jun 2019
You can calculate the inverse and determinant of a any n*n matrix using these inbuilt functions:
det(x)
inv(x)

Alex Mcaulley on 11 Jun 2019
If you have the symbolic toolbox, you can do something like this:
syms a11 a12 a21 a22
x = [a11,a12;a21,a22];
det(x)
ans =
a11*a22 - a12*a21
ans =
[ a22, -a12]
[ -a21, a11]
inv(x)
ans =
[ a22/(a11*a22 - a12*a21), -a12/(a11*a22 - a12*a21)]
[ -a21/(a11*a22 - a12*a21), a11/(a11*a22 - a12*a21)]

R2014a

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