How to create a function that returns values based on a piecewise function?

Hello, I'm having a problem with an exercise featuring f(x), a piecewise function file where I need to create a function with two input arguments (which I will prompt the user for) and output two vectors, f and x.

The vector x should contain values between the start and end at 0.01 increments, and the vector f should contain f(x) for each value of x

Then on a seperate m-file, prompt the user for their domain and plot f(x) based on that domain.

Since this is a homework, I've used a different question on google to get the basic idea and knowledge to solve my own exercise:

Here's what I have so far if helpful or needed:

On m-file: (ignore the velocities, start time and end times and what not, that's just my homework's variables)

clear all; close all; clc;

%Asking for inputs and defining the variables
prompt1 = 'Input the start time';
prompt2 = 'Input the end time';

start_t = input(prompt1);
end_t = input(prompt2);

%Calling the function
[t, v] = VPiecewise(start_t, end_t);

%Plotting the function
plot(t, v)
xlabel('time take with 0.01 smallest division (s)')
ylabel('velocity in ms^-1')
title('v x s')

On function file:

function [t, v] = VPiecewise(start_t, end_t)
t = start_t:0.01:end_t;
...
end

Haven't been able to get much far unfortunately so if anybody would be able to point me towards a right direction, that'd be immensely helpful!

Answer 1

[Azzi Abdelmalek]

f=zeros(size(t))
idx1=t<0
f(idx1)=t(idx1).^2

now do the same for 0<=t & t<=3

[Russell Ng]

That worked absolutely brilliant.