Use the zeros of T_3 to find second degree interpolating polys on [-1, 1] for
f=e^x and f=sin (x)
I am using the formula x_i = cos (((2k-1)pi)/ 2n) to find the zeros. Then I get x0=sqrt3/2 and so is x1. This must be wrong because when constructing my polys I have x0-x1 in the denominator.