ok so here is the problem http://www.flickr.com/photos/23409594@N02/4277189853/ needless to say my answer is not what the book has and i would like to know why. for starts their answer has a natural log in it? i separated the natural log in the problem and took the derivative using the product rule. so where did i go wrong? well take a look at the problem and tell me what you think. sorry its problem number 55.