cheb Calculates the nth-order Chebyshev polynomial at the point x. cheb(n, x) n: Filter order x: Point at which the Chebyshev polynomial is calculater. This is an Octave function. Equation for Chebyshev polynomial is / cos(n acos(x), |x| <= 1 Tn(x) = | \ cosh(n acosh(x), |x| > 1 x can also be a vector. In that case the output will also be a vector of same size as x.