



% 1
A=[1:4; 5:8; 9:12]
TEMP=A(1:2, 1:2);
A(1:2, 1:2)=A(2:3, 3:4);
A(2:3, 3:4)=TEMP


% 2
clc
clear all
x=[0:0.1:10];
a0=1;
a1=2;
a2=3;
y=a0+a1.*x+a2.*x.^2;
an=a2/3;
y=y+an.*rand(1,length(x));
plot(x,y);
grid on;


% 3
clc
clear all
x=[-8*pi:0.1:8*pi];
y=sin(x)./x;
plot(x,y);
grid on;