Polyfitting in MATLAB

clc,clear
disp('Your Name')
t=[1,2,3,4,5,6];
y=[42,83,102,124,129,120];
coef=polyfit(t,y,2);
a1=coef(1);
a2=coef(2);
a3=coef(3);
disp('The values of g and vo are...')
g=-2*a1
vo=a2
yf=polyval(coef,t);
disp(' time y fitting y')
disp(' ')
disp([t',y',yf'])
plot(t,y,'o',t,yf)