function y = chebyshev(n, f, a, b, x)
	X = (b+a)/2 + (b-a)/2 * cos((pi/(2*n)):(pi/n):((2*n-1)*pi/(2*n)));
	Y = f(X);
%	plot(X, Y);
%	hold on;
	y = interpolate(X, Y, x);