que2fan4zhishu.m

signal and system answer

clear
cdnihemean=[25.11672262,28.97088376,30.77802095,32.49002655,34.197839,35.83539109,37.43924133,40.23606289,43.48863216,42.17129146,43.25032931,44.25481142,44.8232313,45.62455339,46.2973856,46.79282586,47.66960357,47.16312936,47.83610598,47.95459593,47.8593765,47.47509451,47.06195044,46.31271118,44.60636045,44.48071463,43.71651647,43.41962809,41.84289189,41.52652511,39.80058087,40.85153974,37.79653794,39.74801305,38.27922569,35.06287554,37.12072255,37.39023859,33.14727569,36.09746535];
s1=zeros(1,11);s2=zeros(1,11);s3=zeros(1,11);
s1(1)=sum(cdnihemean(1:3))/3;
s2(1)=sum(cdnihemean(1:3))/3;
s3(1)=sum(cdnihemean(1:3))/3;
a=zeros(1,40);b=zeros(1,40);c=zeros(1,40);X=zeros(1,40);
A=0.12;
for i=2:40
    s1(i)=A*cdnihemean(i-1)+(1-A)*s1(i-1);
end
for i=2:40
    s2(i)=A*s1(i)+(1-A)*s2(i-1);
end
for i=2:40
    s3(i)=A*s2(i)+(1-A)*s3(i-1);
end
for i=1:40
    a(i)=3*s1(i)-3*s2(i)+s3(i);
    b(i)=A*0.5/(1-A)^2*((6-5*A)*s1(i)-2*(5-4*A)*s2(i)+(4-3*A)*s3(i));
    c(i)=A^2/(1-A)^2*(s1(i)-2*s2(i)+s3(i));
end
for i=38:50   
    X(i)=a(39)+b(39)*(i-39)+0.5*c(39)*(i-39)^2;
end
n=1:50;y=[cdnihemean,X(41:50)];plot(n,y)