Trying to plot function

Hey, so ihave been asked to plot this function

I found a way to do this

    syms x
    y=piecewise(x<-4, 0, -4<=x<3, x+2, x>=3, x-2);
    fplot(y)

and i get this graph

Now, when i try another way to do this

i get this graph

this is the code

    t = linspace(1,1000,1000); %%time
    X1=@(t) (t<=-4).*0+(t>=-4 & t<3).*(t+2)+(t>=3).*(t-2);
    subplot(2,2,1)
    plot (t,X1(t))
    axis([-6 6 -20 20]);

Im trying to understand why this way (the second graph) doesnt work.

Thnx.

[Michael Van de Graaff]

well for one thing, in the second instance you are defining you x-coordinates as going from 1 to 1000, so no, you wont have anything plotted below x=1

[Naor t]

I need 1000 points in the graph between -6<t<6

[Michael Van de Graaff]

also, i'm confused, can you tell me which point on you plot is incorrect?

are you aware that you are plotting only integer X values and the line is just connecting the dot's

[Michael Van de Graaff]

Oh, you need

t = linspace(-6,6,1000);

Answer 1

[Walter Roberson]

You were mislead by two factors:

1. You were not using the same plotting range for both of them
2. You were sampling at a low number of points the conditionals but not for piecewise

    t = -6:6; %%time
    X1=@(t) (t<=-4).*0+(t>=-4 & t<3).*(t+2)+(t>=3).*(t-2);
    subplot(2,2,1)
    plot(t,X1(t))
    axis([-6 6 -20 20]);
    title('discrete using conditionals')
    subplot(2,2,2)
    fplot(X1, [-6 6]);
    axis([-6 6 -20 20]);
    title('continuous using conditionals')
    
    syms x
    y(x) = piecewise(x<-4, 0, -4<=x<3, x+2, x>=3, x-2);
    subplot(2,2,3)
    plot(t, y(t))
    axis([-6 6 -20 20])
    title('discrete using piecewise')
    subplot(2,2,4)
    fplot(y, [-6 6])
    axis([-6 6 -20 20])
    title('continuous using piecewise')

[Naor t]

Ok i understand thank you.

Nut now i have another problem becuase i changed the range.

For some reason i get this problem: Array indices must be positive integers or logical values.

at the plot line.

Y1=X1(t).*(t-1);
subplot(2,2,3)
plot(t,Y1(t))
axis([-6 6 -20 20]);
grid on
title('Subplot 1: Y1')

[madhan ravi]

 plot(t,Y1)

[Naor t]

thanks you!