Here's the question: Find the area of the surface obtained by rotating the curve http://ada.math.uga.edu/webwork2_files/tmp/equations/18/d733a6e52ad8ca260230969bdc3f401.png [Broken] from x=0 to x=9 about the x-axis. I'm supposed to parametrize the curve, using rcos(theta) as x and rsin(theta) as y, at least I think I am. That would give f(x,y) = 3rcos^3(theta),rsin(theta) Then find the partial derivatives with respect to r and theta and find their cross product. Then find the magnitude of the cross product and integrate with limits int[0-2pi] int[0-9]. Is this right? I can't find any information on the internet to do it this way and the book isn't much help either. Thanks.