Respuesta :

sqdancefan
The area of revolution is the integral of 2π(radius)(differential of arc length). [tex] \int\limits^2_1 {2 \pi t^3 \sqrt{(9/4)t^4 +36)}} \, dt[/tex] = (2π/27)*(72^(3/2) -38.25^(3/2)) ≈ 87.1215