Drawing a semi-circle in Matlab about a point

Hi,

There seem to be several different ways to draw a semi-circle according to google, however none of the answers seem to give me what I need.

I would like a semi-circle (from twelve to six, if it were a clock) about the point (5,4),

Does anyone know how to do this?

I have tried rectangle with curvature, polar coodinates and the equation of a circle, but something always seems to go wrong.

This gets me closest:

theta = 0:.01:pi-pi/2; y = 1.8*exp((1j)*theta)+5.8; plot(real(y),imag(y)); axis([0 28 0 15]); axis equal;

However the centre of the circle is on the x axis and not at y=4.5.

Thanks for your help.

Answer 1

[Matt Kindig]

th = linspace( pi/2, -pi/2, 100);
R = 1;  %or whatever radius you want
x = R*cos(th) + 5;
y = R*sin(th) + 4;
plot(x,y); axis equal;

[Stuart]

Fantastic. Thank you.

Answer 2

[Krithik]

th = linspace( pi/2, -pi/2, 100); R = 1; %or whatever radius you want x = R*cos(th) + 5; y = R*sin(th) + 4; plot(x,y); axis equal;