Find the least squares polynomial approximation of degree 2 on the interval [1, 1] for the functions

Question:

Find the least squares polynomial approximation of degree 2 on the interval [−1, 1] for the functions in Exercise 3.
In Exercise 3
a. f (x) = x2 + 3x + 2, [0, 1];
b. f (x) = x3, [0, 2];
c. f (x) = 1/x, [1, 3];
d. f (x) = ex , [0, 2];
e. f (x) = 1/2 cos x + 1/3 sin 2x, [0, 1];
f. f (x) = x ln x, [1, 3].