How can I plot an animated circle?

I want to plot the radius of this circle going round (360 degrees) without the circle showing. So basically just a line fixed at the origin that spins for 2*pi.

I understand that I have to use a for loop between 0 to 2*pi but I don't get which variables I have to use.

Thanks

Answer 1

[Jos (10584)]

Calculate the endpoints

• x = r*cos(2*pi*f*t)
• y = r*sin(2*pi*f*t)

where r, is the radius, f is the frequency and t is the time.

figure
f = 0.3 ; % frequency
r = 2 ;
ph = plot(NaN,NaN,'b-o') ;
axis(1.1*[-r r -r r]) ;
axis square
tic 
while(toc < 10)
   t = toc ;
   ph.XData = [0 r*cos(2*pi*f*t)] ;
   ph.YData = [0 r*sin(2*pi*f*t)] ;
   drawnow
end