How do I do simultaneous equations with unknown variables?

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;

Answer 1

[Siriniharika Katukam]

Hi

"linsolve" does the solving in your case.

Pass K and f as inputs to linsolve.

Do follow this link further:

https://www.mathworks.com/help/symbolic/solve-a-system-of-linear-equations.html