roots of 3*3 matrix determinant
2 Ansichten (letzte 30 Tage)
Ältere Kommentare anzeigen
Cem Eren Aslan
am 5 Jan. 2022
Bearbeitet: David Goodmanson
am 8 Jan. 2022
Hello all,
I have a matrix as follows;
M = [k(1,1)-12*w k(1,2) k(1,3);k(2,1) k(2,2)-2*w k(2,3);k(3,1) k(3,2) k(3,3)-4*w ];
i want to solve and to find three roots of det(M)=0
how can i solve this?
thanks
3 Kommentare
Akzeptierte Antwort
David Goodmanson
am 6 Jan. 2022
Bearbeitet: David Goodmanson
am 8 Jan. 2022
Hi Cern,
I assume you mean the three values of w that give a 0 determinant. Eig works for this.
K = rand(3,3)
c = diag([12 2 4]); % the three coefficients of w down the diagonal
Knew = inv(c)*K % multiply the first row of K by 1/12, second row by 1/2, etc.
w = eig(Knew) % roots
% check, should be small; they are.
det(K-w(1)*c)
det(K-w(2)*c)
det(K-w(3)*c)
K =
0.4169 0.3829 0.3334
0.3801 0.0297 0.9758
0.2133 0.4723 0.5554
Knew =
0.0347 0.0319 0.0278
0.1901 0.0148 0.4879
0.0533 0.1181 0.1389
w =
0.3447
0.0218
-0.1781
In practice, for larger matrices one would use c\K instead of inv(c)*K but the latter expression seems clearer in these circumstances.
0 Kommentare
Weitere Antworten (0)
Siehe auch
Kategorien
Mehr zu Creating and Concatenating Matrices finden Sie in Help Center und File Exchange
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!