que3fan3zhishu.m

signal and system answer

clear
cdnihemean=[26.98175828	29.44800836	30.28969485	31.00725734	31.99188455	32.68291464	33.43120634	35.31488873	37.48628447	37.14249104	36.22203366	36.62470158	36.84210762	37.02045958	37.09906856	38.06407935	38.19913313	38.049148	38.1645914	38.46941108	38.40778028	38.05110555	37.50500154	37.72820859	37.02463598	37.25543644	36.55242702	35.66032605	34.95982096	33.75759742	32.78235198	30.58402667	29.56971744	28.87522278	28.51524179	29.14151031	29.84240704	28.62514132	26.12771919];
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=0.18;
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(40:50)];plot(n,y)