急求matlab程序 二次拟合 曲线的方程

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可见,你提供的数据不适合二次多项式拟合,>> p=polyfit(x,y,1)p =1。0e+006 *0。0012 -2。3969可得直线关系：y=1200*x-2396900