unable to plot diagram in MATLAB

can anybody help me plotting the diagram below in Matlab (just one of them; the colorful one)?

I wrote the code below but the result isn't same.

clc;clear;close all;

t=linspace(0,5,100);

for i=1:length(t)

if (i>=0) && (i<0.5) ;

zp1(i)=0;

else if (i>=0.5) && (i<2.5);

zp1(i)=0.05*sin(2*pi*i);

else if i>=2.5 ;

zp1(i)=0;

end

end

end

end

plot(t,zp1)

Answer 1

[Cris LaPierre]

Work on creating a sin wave that generates the amplitude and frequency you need first. Once you have that, set all y values corresponding to t<0.5 and t>2.5 to zero.

[Tina M]

tnx , can you plz tell me how I can write the code in MATLAB?

[Cris LaPierre]

Can you first create a sin wave with 0.05 amplitude and period of 2 seconds?

[Tina M]

yes, I could plot the first diagram(the colorful one) .

but I had problem in plotting second one. second one follows the same trajectory as the first one with a delay of t=0.1407 s . I wrote the code bellow ,But the result is not the same as the problem's diagram.

clc;clear;close all;

y1=@(t) 0*t.^0 ;

y2=@(t) -0.05*sin(2*pi*t);

y3=@(t) 0*t.^0;

t1=0:0.01:0.6407;

t2=0.6407:0.01:2.6407;

t3=2.6407:0.01:5;

t=[t1 t2 t3];

Zp2=[y1(t1) y2(t2) y3(t3)];

plot(t,Zp2)

axis([0 5 -0.06 0.06]);

grid on

the result is :

[Cris LaPierre]

Let's work with sin only. You are on to something here.

y2=@(t) -0.05*sin(2*pi*t);

Have you realized that a sine wave repeats every seconds? If I want it to repeat every 2 seconds, I can just multiply t by π, making t at 2 seconds .

t=linspace(0,5,100);
y = 0.05*sin(t*pi);
plot(t,y)

A sin wave crosses the x axis at sin(0). You want that to haen at t=0.5. You can adjust the zero crossing by adding or subtracting to t. For example, x=t+0.5 will now move sin(0) to x=0.5.

Put that all together and you get

plot(t+0.5,y)
grid on