各位大侠，我想预测人口，然后通过matlab进行人口拟合（通过lsqcurvefit拟合）建立，首先建立了.m文件，如下

function f=cc2(x, tdata)
   
    f=x(1)/(1+(x(1)/x(2)-1)*exp(-1*x(3)*tdata))
然后执行程序

tdata=1979:1:2010;
cdata=1e+02*[31.41
33.29
36.69
44.95
59.52
74.13
88.15
93.56
105.44
120.14
141.6
167.78
226.76
268.02
335.97
412.71
449.15
482.89
527.75
580.33
632.56
701.24
724.57
746.62
778.27
800.8
827.75
871.1
912.37
954.28
995.01
1037.2
]
x0=[10000000,314100,0.1];
x=lsqcurvefit('cc2',x0,tdata,cdata)
f=cc2(x,tdata)
结果出现以下错误


??? Error using ==> mldivide
Matrix dimensions must agree.

Error in ==> cc2 at 3
    f=x(1)/(1+(x(1)/x(2)-1)*exp(-1*x(3)*tdata))

Error in ==> lsqcurvefit at 209
            initVals.F = feval(funfcn_x_xdata{3},xCurrent,XDATA,varargin{:});

Caused by:
    Failure in initial user-supplied objective function evaluation. LSQCURVEFIT cannot continue.

该怎么改进，求指教！！