%==========================================================================
%  Name：M_P.m
%  
%==========================================================================
clear;close all,
t=-2:0.01:2;
x1=1+cos(2*pi*t)/2+cos(4*pi*t)+2*cos(6*pi*t)/3;
x2=1+cos(2*pi*t+4)/2+cos(4*pi*t+8)+2*cos(6*pi*t+12)/3;;
x3=1+cos(2*pi*t+6)/2+cos(4*pi*t-2.7)+2*cos(6*pi*t+0.93)/3;;
x4=1+cos(2*pi*t+1.2)/2+cos(4*pi*t+4.1)+2*cos(6*pi*t-7.02)/3;;


subplot(221);plot(t,x1,'b');grid on;title('The sequence x1(t)');
subplot(222);plot(t,x2,'r');grid on;title('The sequence x2(t)');
subplot(223);plot(t,x3,'k');grid on;title('The sequence x3(t)');xlabel('Time t');
subplot(224);plot(t,x4,'g');grid on;title('The sequence x4(t)');xlabel('Time t');