what to do when i get unrecognized function or variable

clear;
clc;
close all;
tmin=-3;tmax=5;dt=0.02; 
t=tmin:dt:tmax;
y0=y(t); 
y1=1.5*y(t);
y2=y(2*t);
y3=y(t-0.5); 

Answer 1

[Chunru]

You need to define the function y(t).

y = @(t) cos(t);        % eg. y(t) = cos(t)
tmin=-3;tmax=5;dt=0.02; 
t=tmin:dt:tmax;
y0=y(t); 
y1=1.5*y(t);
y2=y(2*t);
y3=y(t-0.5);