CHEBYSHEVU _ _ _ _ _ _ _ _ _ _ _ _ operator
The ChebyshevU operator returns the nth Chebyshev U Polynomial (of the second kind).
ChebyshevU(3,xx); 2 4*x*(2*x - 1) ChebyshevU(3,4); 496
Chebyshev's U polynomials are computed using the recurrence relati on:
ChebyshevU(n,x) := 2x*ChebyshevU(n-1,x) - ChebyshevU(n-2,x) with
ChebyshevU(0,x) := 0 and ChebyshevU(1,x) := 2x