syms a b;
c = [a b];
A=[1987,2405,2471,2384,2761,2439,2631,2312,2020,2176];
B = cumsum(A); %累加原始数据
n = length(A);
% 产生累加矩阵
for i = 1:(n-1)
C(i) = (B(i) + B(i+1)/2);
end
%计算待定的值
D = A;
D(1) = [];
D=D';
E = [-C;ones(1,n-1)];
c = inv(E*E')*E*D;
c = c';
a = c(1);
b = c(2);
%预测后续数据
F = [];
F(1) = A(1);
for i = 2:(n+10)
F(i) = (A(1)-b/a)/exp(a*(i-1))+b/a;
end
for i = 2:(n+10)
G(i) = F(i) - F(i-1);
end
t1 = 1950:1959;
t2 = 1950:1969;
plot(t1,A,'o',t2,G);
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