plotting piecewise periodic function

How would I plot this function on the range 0<=t<=20?

x= 2(1-t), 0<=t<=1

x= t-1, 1<t<=3

[Walter Roberson]

See https://www.mathworks.com/matlabcentral/answers/1616990-i-want-to-plot-a-piecewise-periodic-function#answer_861420

Answer 1

[Jonas]

you could generate the values for one cycle and then repeat the values using repmat()

Answer 2

[Image Analyst]

Your question did not specify what the value of x is for t > 3 so I'll assume it's zero.

Try this:

% How would I plot this function on the range 0<=t<=20? 
% x= 2(1-t), 0<=t<=1
% x= t-1, 1<t<=3
numElements = 512; % Whatever resolution you want.
% Get t axis.
t = linspace(0, 20, numElements);
% Initialize x to all zeros.
x = zeros(1, numElements);
% Get the first range.
indexRange1 = t >= 0 & t <= 1;
x(indexRange1) = 2 * (1 - t(indexRange1));
% Get the second range.
indexRange2 = t > 1 & t <= 3;
x(indexRange2) = t(indexRange2) - 1;
% Plot x
plot(t, x, 'b-', 'LineWidth', 2);
grid on;
fontSize = 18;
title('x vs. t', 'FontSize', fontSize);
xlabel('t', 'FontSize', fontSize);
ylabel('x', 'FontSize', fontSize);