Papuss's Theorem for Surface Areas

[Larrytsai]

y=sqrt(2x+1), 0≤x≤2

Find the area of the surface by using the second theorem of Pappus.

S= 2pie(row)L

I cannot find what the centroid is, i have length as 2

 

[LCKurtz]

Find the area of what surface? A graph in the xy plane is not a surface. And your arc length isn't correct.