%用北太天元軟件研究中國(guó)人口數(shù)據(jù)的變化

clear;

clf;

close all;

hold off

yp = [ 2022 141151.0

2021 141236.0

2020 141110.0

2019 140774.5

2018 140276.0

2017 139621.5

2016 138779.0

2015 137986.0

2014 137186.0

2013 136324.0

2012 135419.0

2011 134503.5

2010 133770.5

2009 133126.0

2008 132465.5

2007 131788.5

2006 131102.0

2005 130372.0

2004 129607.5

2003 128840.0

2002 128040.0

2001 127185.0

2000 126264.5

1999 125273.5

1998 124193.5

1997 123007.5

1996 121755.0

1995 120485.5

1994 119183.5

1993 117844.0

1992 116497.0

1991 115078.0

1990 113518.5

1989 111865.0

1988 110163.0

1987 108403.5

1986 106679.0

1985 105104.0

1984 103682.5

1983 102331.0

1982 100863.0

1981 99388.5

1980 98123.5

1979 96900.5

1978 95616.5

1977 94345.5

1976 93068.5

1975 91639.5

1974 90035.0

1973 88194.0

1972 86203.0

1971 84110.5

1970 81831.5

1969 79602.5

1968 77451.0

1967 75455.0

1966 73540.0

1965 71518.5

1964 69835.5

1963 68233.5

1962 66577.0

1961 66033.0

1960 66707.0

1959 65495.4 ];

yp = yp(end:-1:1,:);

% 人口

p = (yp(:,2))' ;

% 時(shí)間

t = (yp(:,1))' ;

% 畫(huà)出中國(guó)人口

plot(t,p,'bo');

title("1959-2022 中國(guó)人口(單位萬(wàn))");

ylabel('人口:萬(wàn)');

xlabel('年');

擬合多項(xiàng)式 = polyfit(t,p, 2);

hold on

x=t(1):5:2172;

y = polyval(擬合多項(xiàng)式,x);

plot(x,y,'-r*')

zerot = find(y<0) ;

fo = zerot(1);

text(x(fo)-20,y(fo), [num2str(x(fo)), '年,人口開(kāi)始為負(fù)數(shù)'],'FontSize',24)

hold off