time=[0,0.5,1,1.5,2,2.5,3,3.5,4,4.5,5,5.5,6,6.5,7,7.5,8,8.5,9,9.5];
temperture=[50.4,49.5,48.6,47.9,47,46.2,45.6,44.9,44.1,43.3,42.3,41.6,40.8,40.1,39.4,38.9,38.2,37.5,36.8,35.9];
P=polyfit(time, temperture, 3);
xi=0:.2:10;
yi= polyval(P, xi);
plot(xi,yi,time,temperture,'r*');