help with plotting function of time

" Plot on the same graph the motion of x4(t) in the original domain as well as the eigenspace {x4}B (t)." Really confused on how to even do this. Please help. Shown is my code.

[Geoff Hayes]

Please include (via attachment or by copying and pasting) your code to this question rather than including screen shots of the code.

[random1072]

M = [11 0 0 0 0 0 0;
     0 18 0 0 0 0 0;
     0 0 17 0 0 0 0;
     0 0 0 17 0 0 0;
     0 0 0 0 13 0 0;
     0 0 0 0 0 10 0;
     0 0 0 0 0 0 12]
 
K = 108; % altering stiffness so system will become stable

% K value that makes system stable = 108 N/M

% initialize the end masses as pushing outward (i.e. x1 @ t=0 = −1 unit and x7 @ t=0 = +1 unit) and track 
% the behavior of the middle mass x4 as a function of increasing time

 

K_Matrix_New = [(-K-K) K 0 0 0 0 0; % new K matrix where x1 and x7 are pushed out
            K (-K-K) K 0 0 0 0;
            0 K (-K-K) K 0 0 0;
            0 0 -K 0 K 0 0;
            0 0 0 -K (K+K) -K 0;
            0 0 0 0 -K (K+K) -K;
            0 0 0 0 0 -K (K+K) ]
        
K_tilde_New = M^(-1/2)*K_Matrix_New*M^(-1/2)

e = eig(K_tilde_New) % gives my eigenvalues where none are imaginary
w_new = sqrt(e) % gives the value of the frequencies +/-