Concept started with 𝑇0=1 and 𝑇1=𝑥 𝑇𝑘+1(𝑥)=2𝑥𝑇𝑘(𝑥)−𝑇𝑘−1(𝑥) or 𝑇𝑗(𝑥)=cos(𝑗⋅arccos(𝑥)) therefore it always only defined in [−1,1] Weight for first-kind Chebyshev Polynomials 𝑤(𝑡)=√1−𝑡2
