How to plot sine graph by using for loop?

I tried to use a for loop to plot a sine graph. The values are generated but then when I try to graph them, I get either an error or no graph. Here's my code:

for i = 0:0.1:2*pi

m=sin(i);

n=i;

plot(n,m,'-r');

hold on

end

[Mohammad Alhashash]

do you want to animate the sine graph or just plot it

[Xing Xing]

I just want to plot it with this for loop.

Answer 1

[Alex Mcaulley]

You don't need a loop, just:

theta = 0:0.1:2*pi;
plot(theta,sin(theta))

[Xing Xing]

I know but if I want to use this for loop, how to plot it ?

[Alex Mcaulley]

It make no sense, but one option is:

plot(0,0);
h = findobj(gca,'Type','Line');
for i = 0:0.1:2*pi 
    m=sin(i);
    n=i;
    set(h,'XData',[get(h,'XData'),n])
    set(h,'YData',[get(h,'YData'),m])
end

[Xing Xing]

I was tried my code in old version of MATLAB and it works, but in 2018b which is the version I have right now it doesn't work. It's really weird and I don't understand. Thank you for your help and option! Really appreciated!

[Alex Mcaulley]

With your code, you are generating one point in each iteration, not a unique line. If you want to see it:

for i = 0:0.1:2*pi 
m=sin(i);
n=i;
plot(n,m,'*r');
hold on
end 
numel(findobj(gca,'Type','Line'))

[Xing Xing]

OH, I see! Thanks!

[AZEEM IMTIAZ]

you need to define t as a continuous variable in the first line then apply for loop on the frequency as discrete values. so that each frequency point will sweep over the time that you have defined in the first line. hope this helps!

t=0:0.04:5;

hold on

for f=[0.7 1 1.5 2]

y=cos(2*pi*f*t);

plot(t,y)

end

Answer 2

[Mohammad Alhashash]

maybe that is what you need.

t= 0:0.01:2*pi;
m =sin(t);
t_plot = NaN(1,length(t));
m_plot = NaN(1,length(m));

u = 1;
for i = 1:length(t)
    cla
    t_plot(i) = t(u);
    m_plot(i) = m(u);
    plot(t_plot,m_plot)
    drawnow
    u = u + 1;
end

[Xing Xing]

I understand what is my problem and thank you for your answer!