# How do I do simultaneous equations with unknown variables?

5 visualizaciones (últimos 30 días)
Gowutheyaan Ratnasingam el 18 de Nov. de 2019
Respondida: Siriniharika Katukam el 21 de Nov. de 2019
I have worked out a global stiffness matrix and the global force vector. After this I need to do an equation [K][q] = {f}
Where {q} =
q1
q2
q3
Where q1 is equal to zero, and the other two are values to be found, how do I find these values? When I try, Matlab keeps on saying q2 etc. are undefined. It also doesn't seem to accept F = K*Q for some reason too
Code so far:
Edof = [1 1 2; 2 2 3];
K = zeros (3,3);
F = zeros (3,1);
F (2) = 4;
F (3) = 2;
k1 = 60;
k2 = 30;
Ke1 = [k1 -k1; -k1 k1];
Ke2 = [k2 -k2; -k2 k2];
K(1:2,1:2) = Ke1;
K(2:3,2:3) = K(2:3,2:3) + Ke2;
##### 0 comentariosMostrar -2 comentarios más antiguosOcultar -2 comentarios más antiguos

Iniciar sesión para comentar.

### Respuestas (1)

Siriniharika Katukam el 21 de Nov. de 2019
Hi
"linsolve" does the solving in your case.
Pass K and f as inputs to linsolve.
##### 0 comentariosMostrar -2 comentarios más antiguosOcultar -2 comentarios más antiguos

Iniciar sesión para comentar.

### Categorías

Más información sobre Programming en Help Center y File Exchange.

R2018b

### Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by