figure(5)
x=linspace(-8,8,100);
y=linspace(-8,8,100);
plot(2*sqrt(y.^2/4^2+1),y);
hold on
plot(-2*sqrt(y.^2/4^2+1),y);
plot(x,2*x)
plot(x,-2*x)
axis equal
title('Eksempel 1')
hold off

figure(6)
t=linspace(0,2*pi,100);
plot(-1+1.5*cos(t),-1+3*sin(t))
axis equal
title('Eksempel 2')