Write a MATLAB code where I'll show the plot or graph.

Here is the condition. Now write a MATLAB code where I'll show the plot or graph.

y(x) = 3.75x+10 at 0<x<2

y(x) = -2.75x+22.5 at 2<x<4

y(x) = 12.5 at 4<x<6

y(x) = 2.5x-2.5 at 6<x<8

The plot or graph will be like this.

Answer 1

[Walter Roberson]

x = rand() * 2

x = 0.0101

y = @(t) -42*x + 53;
T = linspace(-3, 3);
for idx = 1 : length(T)
    Y(idx) = y(T(idx));
end
plot(T, Y)
ylim([-90 90])

Why? Well, you define y as functions of t but there is no t in the formulas, so we have to assume that the items such as 0 < x < 2 mean that x is to some one random element of the given range.

[AZ Sajjad]

I edited my question. Now would you help me out?

[Walter Roberson]

I would point out that I illustrated several important points:

• constructing anonymous functions
• defining a range of values to evaluate over
• evaluating a non-vectorized function over a non-integer list of values
• plotting given a range and associated values
• adjusting plot y view to make sure the plot is entirely in-frame

The only extra thing you need beyond this is to either use hold on or to plot multiple lines in the same plot() call. Oh, and how to pass color information to plot(). See the plot() documentation.

Answer 2

[Sam Chak]

Hi @AZ Sajjad

This is a piecewise linear function because it is defined on a sequence of intervals, and there are a few ways to plot it. However, for beginners, I think that the following approach is easy to understand because you only need to specify the interval and expression for each linear function. I'll show how to plot the first three functions (you will handle the fourth one). Also, please note that the piecewise function contains two jump discontinuities, one at and another at .

If you want the linear functions to be continuous on their corresponding intervals, you will need to modify the equations so that and .

x1 = 0:0.01:2;
y1 = 3.75*x1 + 10;              % 0 < x < 2

x2 = 2:0.01:4;
y2 = - 2.75*x2 + 22.5;          % 2 < x < 4

x3 = 4:0.01:6;
y3 = 12.5*ones(1, numel(x3));   % 4 < x < 6

plot([x1, x2, x3], [y1, y2, y3])
xlabel('x')
ylabel('y')
title('Piecewise function')
label = {'17.5','17.0','11.5'};
yline([17.5 17.0 11.5], '--', label, 'color', '#A1B2C3')