the equation is . I found that x=sqrt(1-y) and that x'=-1/(2*sqrt(y-1)).
I've been using integral(2*pi*x*sqrt(1+x'^2)) but i keep just getting mixed up with my calculations.
help would be appreciated.
If you rotate this function about the y-axis, each cross-section parallel to the x-axis will be a circle. The circumference of each circle is , and if you add up all these circumferences over then you will get the total surface area. So