T_n( cos(theta) ) = cos(n theta) where T_n is the nth Chebyshev polynomial of the first kind Posted on 2022/03/11 by Carl Robitaille T_n( cos(theta) ) = cos(n theta) where T_n is the nth Chebyshev polynomial of the first kind.— Algebra Etc. (@AlgebraFact) March 2, 2022