Evaluate Polynoms and Regression

Let 3x3 -2x2 + 2x +1 be the polynomial p, we can calculate p(3):

>>> np.polyval([3,-2,2,1], 3)

70

>>>

Regression (using least square method):

>>> x = [-3, -1, 0, 1, 3]

>>> y = [9,1,0,1,9]

>>> np.polyfit(x,y,2)

array([ 1.00000000e+00, -8.75052981e-18, 0.00000000e+00])

>>> y = [12,4,3,4,12]

>>> np.polyfit(x,y,2)

array([ 1.00000000e+00, -7.40148683e-16, 3.00000000e+00])

>>>