maybe this can help
By Chebyshev points we shall mean the set of points in [−1,1] defined by
xj=−cos(jπ/N), 0≤j≤N,
where N≥1 is an integer. (If N=0, we take x0=0.) A fuller name is that these are Chebyshev points of the second kind. (Chebfun also enables computations based on Chebyshev points of the first kind; see Section 8.9.) Through any data values fj at these points there is a unique polynomial interpolant p(x) of degree ≤N, which we call the Chebyshev interpolant. In particular, if the data are fj=(−1)n−j, then p(x) is TN(x), the degree N Chebyshev polynomial, which can also be defined by the formula TN(x)=cos(Ncos−1(x)). In Chebfun, the command chebpoly(N) returns a chebfun corresponding to TN, and poly returns coefficients in the monomial basis 1,x,x2,…. Thus we can print the coefficients of the first few Chebyshev polynomials like this:
taken from here
