跟他的问题一样,y=a/(1 (a/566-1)*exp(-r*t))用matlab作图x=[1978:1:2010];y=[566 632 745 755 769 789 985 1110 1313 1428 1782 1920 2150 2292 2601 3149 4338 5145 5809 6241 6854 7656 8772 10007 11374 12567 14332 16614 19228 22844 26404 29688 32074
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跟他的问题一样,y=a/(1 (a/566-1)*exp(-r*t))用matlab作图x=[1978:1:2010];y=[566 632 745 755 769 789 985 1110 1313 1428 1782 1920 2150 2292 2601 3149 4338 5145 5809 6241 6854 7656 8772 10007 11374 12567 14332 16614 19228 22844 26404 29688 32074
跟他的问题一样,y=a/(1 (a/566-1)*exp(-r*t))用matlab作图
x=[1978:1:2010];
y=[566 632 745 755 769 789 985 1110 1313 1428 1782 1920 2150 2292 2601 3149 4338 5145 5809 6241 6854 7656 8772 10007 11374 12567 14332 16614 19228 22844 26404 29688 32074];
跟他的问题一样,y=a/(1 (a/566-1)*exp(-r*t))用matlab作图x=[1978:1:2010];y=[566 632 745 755 769 789 985 1110 1313 1428 1782 1920 2150 2292 2601 3149 4338 5145 5809 6241 6854 7656 8772 10007 11374 12567 14332 16614 19228 22844 26404 29688 32074
>> y=[556,632,745,755,769,789,985,1110,1313,1428,1782,1920,2150,2292,2601,3149,4338,5145,5809,6241,6854,7656,8772,10007,11374,12567,14332,16614,19228,22844,26404,29688,32074]';
x=[1978:1:2010]';
st_ = [32074 0.5];
ft_ = fittype('a/(1+(a/556-1)*exp(-b*(x-1978))) ' ,...
'dependent',{'y'},'independent',{'x'},...
'coefficients',{'a','b'});
[cf_ ,good]= fit(x,y,ft_ ,'Startpoint',st_)
h_ = plot(cf_,'fit',0.95);
legend off; % turn off legend from plot method call
set(h_(1),'Color',[1 0 0],...
'LineStyle','-','LineWidth',2,...
'Marker','none','MarkerSize',6);
hold on,plot(x,y,'*')
cf_ =
General model:
cf_(x) = a/(1+(a/556-1)*exp(-b*(x-1978)))
Coefficients (with 95% confidence bounds):
a = 2.654e+007 (-1.936e+009,1.989e+009)
b = 0.1273 (0.1249,0.1296)
good =
sse:7.581000406528857e+006
rsquare:0.997101925993753
dfe:31
adjrsquare:0.997008439735487
rmse:4.945183517429948e+002