What is the correct equation?

w1=104; s=0.3; u=1;

>> w2=w1*(1-(s^2))^(1/2)

w2 =

99.2097

>> y=(s)/(1-(s^2))

y =

0.3297

>> t=linspace(0,0.2,100);

>> x=u*(1-exp(-s*w1*t)*(cos(w2*t)-y*sin(w2*t)));

Error using *

Incorrect dimensions for matrix multiplication. Check that the number of columns in the first matrix matches the

number of rows in the second matrix. To perform elementwise multiplication, use '.*'.

This is the equation I am trying to input:

x(t)=u[1-e^(-sw1t)*(cos(w2t)-ysin(w2t))]

What is the correct equation for x?

Answer 1

[Ollie A]

You have a variable t in your equation which is a vector. In order to multiply vectors in MATLAB you must use the syntax .*. In your case, the equation should be:

x=u*(1-exp(-s*w1*t).*(cos(w2*t)-y*sin(w2*t)));

I believe that should fix it.

Answer 2

[Walter Roberson]

x=u*(1-exp(-s*w1*t).*(cos(w2*t)-y*sin(w2*t)));

Answer 3

[Jim Riggs]

Variable t is a vector. If you want to perform element-wise multiplication on t, use .* in stead of *

try

x=u.*(1-exp(-s.*w1.*t).*(cos(w2.*t)-y.*sin(w2.*t)));