Determining the Surface Area of a Solid of Revolution
Key Questions

If a surface is obtained by rotating about the xaxis from
#t=a# to#b# the curve of the parametric equation#{(x=x(t)),(y=y(t)):}# ,then its surface area A can be found by
#A=2pi int_a^by(t)sqrt{x'(t)+y'(t)}dt# If the same curve is rotated about the yaxis, then
#A=2pi int_a^b x(t)sqrt{x'(t)+y'(t)}dt#
I hope that this was helpful.