"Displaying" in this context typically means to print some data to the command window. There are several ways to achieve this, such as:
- any expression will display its output when it does NOT have a trailing semicolon.
- calling disp with some input data
- calling fprintf with some input data
- error or warning calls.
So to fulfill the first part of the assignment "...first display.." you would need something like this:
function myfunction(a,b,n) % no output argument!
...
LaLa = zeros(1,n);
index = 3:n;
Lala(index)= Lala(index-1) + Lala(index-2) % no semicolon!
and for the second part you can add the semicolon (so it does NOT display any more) and add the output argument so that it returns those values:
function LaLa = myfunction(a,b,n) % with output argument!
...
LaLa = zeros(1,n);
index = 3:n;
Lala(index)= Lala(index-1) + Lala(index-2); %semicolon!
"However, I don't know how to tell if Lala is a vector or not?"
A vector has size 1xN or Nx1. According to that LaLa is a vector, because that is how you defined it using zeros(1,n). If n is a scalar then 1:length(n) is also a scalar (you did not tell us what size n is).
