Help in Matlab Assigment (Plot Circles)

First Plot Circles

a-) Write MATLAB function called [x,y]=createCircle(center,r). The circle should be centered at center (1x2 row vector). Return x and y coordinates of the circle and then plot the circle. Remember that for a circle at origin (0,0) following equation is true

x(t) = cos(t)

y(t) = sin(t) for t = [0,2π].

Now, you need to find out how to scale and translate the circle.

Second

[Adam Danz]

We don't do other people's homework. After you get this started on your own, if you get stuck, show us your code and explain what's wrong and we can give you hints.

[Enes Balci]

Oh ok then, is it ok for this question?

function h = circle(x,y,r)
hold on
t = 0:2*pi;
xunit =r*cos(t);
yunit =r*sin(t);
h = plot(xunit, yunit);
hold off

[Adam Danz]

That function should plot a circle centered at (x,y) with radius r.

[Image Analyst]

It should (is supposed to), but it doesn't. And it should also take and return vectors, which it doesn't yet.

Close, but see my corrections in my answer below.

[Adam Danz]

ah, well, t needs to be incremented and axis equal will help, too.

t = 0:.01:2*pi;  % or linspace()

Answer 1

[Image Analyst]

This is a frequently asked question, so see the FAQ

For your code, you need to modify it to take more points because going from 0 to 2*pi in steps of 1 makes for a pretty chunky circle. Make it like 1000 steps with linspace(). You also need to add x center to xunit and the y center to yunit to get the center in the right place, and pass in a 1x2 vector and pass out the coordinates of the circle's perimeter.

function [xunit, yunit] = circle(xy,r)
hold on
t = linspace(0, 2*pi, 1000); % 1000 points between 0 and 2*pi
xunit = r * cos(t) + xy(1);
yunit = r * sin(t) + xy(2);
plot(xunit, yunit);
grid on;
hold off

Then you call call it like

[x, y] = circle([10, 20], 5)

[Adam Danz]

axis equal

so it looks like a circle