function expmulti( hi, lo, k ) {
	var r;
	var t;
	var c;
	var y;

	r = hi - lo;
	t = r * r;
	c = r - ( t*polyvalP( t ) );
	y = 1.0 - ( lo - ( (r*c)/(2.0-c) ) - hi );

	return ldexp( y, k );
}
Computes \\(e^{r} 2^k\\) where \\(r = \mathrm{hi} - \mathrm{lo}\\) and \\(|r| \leq \ln(2)/2\\).

@private
@param {number} hi - upper bound
@param {number} lo - lower bound
@param {integer} k - power of 2
@returns {number} function value