how can i plot the line in different colours

close all; clear all; clc;

x = -5:0.01:5;
y = zeros(1,length(x));
for i = 1:length(x)
    if(x(i) < -1)
        y(i) = x(i) + 2;
        hold on
    elseif(x(i) <= 2 )
        y(i) = x(i)^2;
        hold on
    elseif(x(i) > 2)
        y(i) = -2*x(i) + 8;
        hold on
    end

end
plot(x,y)

[Hannes Arnar]

How can i make the line bigger ?

close all; clear all; clc;

x = -5:0.01:5; y = zeros(1,length(x));

cond1 = x < -1; cond2 = x >= -1 & x <= 2; cond3 = x > 2; y( cond1 ) = x( cond1 ) + 2; y( cond2 ) = x( cond2 ).^2; y( cond3 ) = -2 * x( cond3 ) + 8; figure; plot( x( cond1 ), y( cond1 ), 'r:' ) hold on plot( x( cond2 ), y( cond2 ), 'b:' ) plot( x( cond3 ), y( cond3 ), 'g:' )

Answer 1

[Adam]

Just plot three different lines and give them each a colour rather than plotting them in a single instruction. You can also put the numbers into the vector without requiring a for loop too e.g.

cond1 = x < -1;
cond2 = x >= -1 & x <= 2;
cond3 = x > 2;

y( cond1 ) = x( cond1 ) + 2;
y( cond2 ) = x( cond2 ).^2;
y( cond3 ) = -2 * x( cond3 ) + 8;

figure;
plot( x( cond1 ), y( cond1 ), 'r' )
hold on
plot( x( cond2 ), y( cond2 ), 'g' )
plot( x( cond3 ), y( cond3 ), 'b' )

Answer 2

[Image Analyst]

Regarding your question about line width in your comment above, to make the line bigger (thicker), change the 'LineWidth' option:

plot(x(cond3), y(cond3), 'g:', 'LineWidth', 3);