4) Find the area of the surface obtained by rotating the curve from http://webwork.umemat.maine.edu/webw...c67fef88e1.png to http://webwork.umemat.maine.edu/webw...286ca42401.png about the http://webwork.umemat.maine.edu/webw...dd0b8b8e91.png-axis.

Any idea about the answer? I try to do it and my answer always turn out wrong. I don't know why:(