Question

I need help with problem plz

Answer 1

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