Calculate by hand the least squares polynomial function gx r

Calculate by hand the least squares polynomial function, g(x), representing the data for these cases:

a) g(x) = a0

b) g(x) = a0 + a1x

c) g(x) = a1x + a3x^3

Solution: in given data pairs the least data is (1,3)

put this data in first polynomial (constent)g(x)=1

put in (1,3) second polynomial g(x)=1+3x

put (3,6) & (5,8) in third polynomial g(x)=3+5x³

and in given polynomial the least squre polinomial is g(x)=a0+a2x²

putting the data in given in this polynomial is g(x)=1+6x²

this is least squre polynomial