function chepolsum( n, t ) {
	var tt;
	var u0;
	var u1;
	var u2;
	var k;

	u0 = 0.0;
	u1 = 0.0;
	tt = t + t;
	k = n;
	do {
		u2 = u1;
		u1 = u0;
		u0 = ( tt*u1 ) - u2 + A[ k ];
		k -= 1;
	} while ( k >= 0 );
	return ( u0-u2 ) / 2.0;
}
Computes the sum of a Chebyshev polynomial.

@private
@param {PositiveInteger} n - degree of polynomial
@param {number} t - input value
@returns {number} Chebyshev sum