年份195419551956195719581959196019611962总人口60.261.562.864.666.067.266.265.967.3年份196319641965196619671968196919701971总人口69.170.472.574.576.378.580.783.085.2年份197219731974197519761977197819791980总人口87.189.290.992.493.795.096.25997.598.705年份198119821983198419851986198719881989总人口100.1101.654103.008104.357105.851107.5109.3111.026112.704年份199019911992199319941995199619971998总人口114.333115.823117.171118.517119.850121.121122.389123.626124.761年份1999200020012002200320042005总人口125.786126.743127.627128.453129.227129.988130.756clear;clc;t=0:17;x=[26.4126.9427.4627.9928.5129.0430.4831.9133.3534.7836.2237.6639.0940.5341.7642.9943.9044.94];f=@(p,t)(p(1)./(p(2)+p(3)*exp(-p(4)*t))).^(1/p(5));plot(t,x,'ko');holdon;p=fminsearch(@(p)sum((f(p,t)-x).^2),ones(1,5));cc=corrcoef(t,f(p,t));h=ezplot(@(t)f(p,t),[0,17]);p=lsqcurvefit(f,ones(1,5),t,x,[],[]);cc=corrcoef(t,f(p,t));ezplot(@(t)f(p,t),[0,17]);clear;clc;A='kdbac';t=0:17;x=[26.4126.9427.4627.9928.5129.0430.4831.9133.3534.7836.2237.6639.0940.5341.7642.9943.9044.94];opt=optimset('display','off');f=@(p,t)(p(1)./(p(2)+p(3)*exp(-p(4)*t))).^(1/p(5));plot(t,x,'ko');holdon;p=fminsearch(@(p)sum((f(p,t)-x).^2),ones(1,5),opt);cc=corrcoef(t,f(p,t));disp('estimatedbyfminsearch:');disp(A);disp(p);disp('correlationcoefficientis:');disp(cc(2));h=ezplot(@(t)f(p,t),[0,17]);set(h,'linestyle',':','color','r')p=lsqcurvefit(f,ones(1,5),t,x,[],[],opt);cc=corrcoef(t,f(p,t));disp('estimatedbylsqcurvefit:');disp(A);disp(p);disp('correlationcoefficientis:');disp(cc(2));ezplot(@(t)f(p,t),[0,17]);legend('originaldata','estimatedbyfminsearch','estimatedbylsqcurvefit','location','southeast')title('curvefitting')