x=[1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009];y=[5156 5138 6526 7434 8475 9688 10703 11384 12343 13630 15558 18472 19820];>> p=polyfit(x,y,2)Warning: Polynomial is badly conditioned. Add points with distinct Xvalues, reduce the degree of the polynomial, or try centeringand scaling as described in HELP POLYFIT.> In polyfit at 80p =1.0e+008 *0.0000 -0.0023 2.3021可見，你提供的資料不適合二次多項式擬合，>> p=polyfit(x,y,1)p =1.0e+006 *0.0012 -2.3969可得直線關係：y=1200*x-2396900
x=[1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009];y=[5156 5138 6526 7434 8475 9688 10703 11384 12343 13630 15558 18472 19820];>> p=polyfit(x,y,2)Warning: Polynomial is badly conditioned. Add points with distinct Xvalues, reduce the degree of the polynomial, or try centeringand scaling as described in HELP POLYFIT.> In polyfit at 80p =1.0e+008 *0.0000 -0.0023 2.3021可見，你提供的資料不適合二次多項式擬合，>> p=polyfit(x,y,1)p =1.0e+006 *0.0012 -2.3969可得直線關係：y=1200*x-2396900