## Surface area of solid of revolution

If we revolve a curve y=f(x) on the interval [a,b] about **x axis,** then we calculate area of resulting surface by breaking the curve into pieces as we did for arc length. A piece of curve of length dS at an average distance y from x axis traces out a surface that is well approximated by a slice of a cone whose area is approximated by 2πydS.

For detailed explanation and examples please visit… https://celestialtutors.com/subtopic/surface-area/