function dotProduct(v1:Vector., v2:Vector.):Number{    if(v1.length != v2.length) return NaN;    var sum:Number = 0;    for(var i:uint = 0; i < v1.length; i++)        sum += v1[i]*v2[i];    return sum;}trace(dotProduct(Vector.([1,3,-5]),Vector.([4,-2,-1])));