figure(1)
subplot(2,2,1)
x=linspace(0,2*pi,50);
y1=sin(x);
y2=sin(x).*sin(x);
y3=sin(2*x);
plot(x,y1,'red +' , x,y2,'blue -' , x,y3 ,'green *')
legend('y1' , 'y2', 'y3')

subplot (2,2,2)
t=linspace(-pi,pi,50);
y4=sin(3*t);
polar(t,y4,'r')

subplot(2,2,3)
a=[1 4 8]
B=rand(3,3)
bar(a,B)

subplot(2,2,4)
k=[20 30 10 40]
pie(k)