% polfig3.m   96/07/21
%
% Create a figure in polar coordinates with
% a<=r<=b and g_1(r)<=theta<=g_2(r)
%
    con=pi/180;
    a=1;
    b=2;
    r=a+(b-a)*(0:20)/20;
    g1=(30+10*cos(2*r))*con;
    g2=(60+10*sin(2*r))*con;
    lg=length(g1);
    theta1=g1(1)+(g2(1)-g1(1))*(0:20)/20;
    theta2=g1(lg)+(g2(lg)-g1(lg))*(0:20)/20;

    hold off;
    plot(a*cos(theta1),a*sin(theta1),'w-');
    hold on
    plot(b*cos(theta2),b*sin(theta2),'w-');
    plot(r.*cos(g1),r.*sin(g1),'w-');
    plot(r.*cos(g2),r.*sin(g2),'w-');
    axis([-.5 2.5 -.5 2.5]);
    axis square;
    plot([-.5 5],[0 0],'w-');
    plot([0 0],[-.5 5],'w-');

% Text

%    xlabel('x');
%    ylabel('y');
    text(2,-.15,'x');
    text(-.2,2,'y');
    text(1.7,1.3,'r=b');
    text(.47,.56,'r=a');
    text(1.4,.35,'g_1(r)');
    text(.5,1.5,'g_2(r)');
