How to plot points and circles in the same image?

Hi everyone, I'm not very experienced in matlab and am having a hard time trying to find a solution to my problem online, so I come to you. I hope this is not too dumb. ':)

I have the certer coordinates and radii of three circles I need to plot. I also have the coordinates of a series of points I need to check visually if they are in a certain area determined by the circles. What I need in the end up with is something like this:

I can plot the circles and I can plot the points, but I'm not being able to do both. I've tried to use "hold on" between a plot and the other but I can't see exactly why it's not working.

I have drawn the circles using the viscircles function which I'm not very familiar with, so perhaps my problem is here.

I appreciate very much any help possible!

Answer 1

[Fangjun Jiang]

%%
c=[0,0;-3 0;2 0];
r=[5;2;3];
viscircles(c,r);
hold on;
plot(10*rand(20,1)-5,10*rand(20,1)-5,'x');

[Lucas Prata Ferreira]

This works perfectly, and I have absolutely no idea of what I was doing wrong. xD

Thanks a lot!

[Image Analyst]

Neither do we since you forgot to post your original code, but glad it's working.

viscircles doesn't blow away existing graphics like plot() does. Some functions are like that -- I think line(), xline() and yline() also don't blow away existing content. So it you do plot() first, you don't need hold on:

c=[0,0;-3 0;2 0];
r=[5;2;3];
plot(10*rand(20,1)-5,10*rand(20,1)-5,'x');
viscircles(c,r);

If you use viscircles() first, plot would blow it away, so in that case you would need to put hold on.