matlab polyfit() 函数多项式系数问题答:clc; close all; clear all;warning off all;x = [1999,2000,2001,2002,2003,2004,2005,2006,2007,2008]';y = [5093.32,5331.58,5768.83,6282.88,7178.26,8112.24,9184.55,10771.79,12718.36,14159.46]';p = polyfit(x, y, 2);y1 = polyval(p, x);plot(x, y, '*', ...