MATLAB画圆

***************************************这是一种思路*****************************************

通过坐标变换

function H=circle(center,radius,NOP,style)
%---------------------------------------------------------------------------------------------
% H=CIRCLE(CENTER,RADIUS,NOP,STYLE)
% This routine draws a circle with center defined as
% a vector CENTER, radius as a scaler RADIS. NOP is
% the number of points on the circle. As to STYLE,
% use it the same way as you use the rountine PLOT.
% Since the handle of the object is returned, you
% use routine SET to get the best result.
%
%   Usage Examples,
%
%   circle([1,3],3,1000,':');
%   circle([2,4],2,1000,'--');
%
%   Zhenhai Wang <[e-mail]>
%   Version 1.00
%   December, 2002
%---------------------------------------------------------------------------------------------

if (nargin <3),
 error('Please see help for INPUT DATA.');
elseif (nargin==3)
    style='b-';
end;
THETA=linspace(0,2*pi,NOP);
RHO=ones(1,NOP)*radius;
[X,Y] = pol2cart(THETA,RHO);
X=X+center(1);
Y=Y+center(2);
H=plot(X,Y,style);
axis square;

 

****************************************另一种思路*****************************************

通过sin(x)^2+cos(x)^2=1也可以画出圆

x=linspace(0,10,100);
y=linspace(0,10,100);
plot(sin(x),cos(y));
axis equal;