Error when using 2 functions as input in lsim

Whenever I run this program, it gives me an error saying:

Error using *. Inner matrix dimensions must agree.

Could someone please explain how else i'm supposed to have the input as exp(-2t)*cos(t)?

Fs = 100;
   dt = 1/Fs;
   StartTime = -5;
   StopTime = 15;
   t = StartTime:dt:StopTime-dt;

A = [0 1 0;0 0 1;-1 -4 -2]; 
B = [0;0;1]; 
C = [1 0 0]; 
D = zeros(1,1);

[nom, denom] = ss2tf(A,B,C,D,1);
sys = ss(A,B,C,[]);
t=linspace(0,6);
u = (exp(-2*t) * cos(t));

lsim(sys,u,t)

[Birdman]

In the previous question, have you run my simulink model?

Answer 1

[Walter Roberson]

The * operator is the algebraic matrix multiplication operator. A*B with A being m x n and B being p x q, (m x n) * (p x q) requires that m and p are the same, and produces an output that is m x q . This is expressed as "the two inner dimensions must be the same"

When you have (exp(-2*t) * cos(t)) you are asking to matrix-multiply something that is (1 x length(t)) * (1 x length(t)) . For this to work, length(t) would have to match 1 -- so scalar * scalar. That is not the case for you.

What you want is

u = (exp(-2*t) .* cos(t));

the .* operator is element-by-element multiplication, equivalent to u(K) = exp(-2*t(K)) * cos(t(K)) for scalar K.