>> x = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
>> y = [1, 6, 17, 34, 57, 86, 121, 162, 209, 262, 321];
>> polyfit(x,y,2)
ans =
2.999999999999998 2.000000000000019 0.999999999999956