Answer: 8π.
- A 8π
- B 16π
- C 4π
- D 12π
Correct answer: A. 8π
Explanation: Disk method: V = π∫₀⁴[√x]²dx = π∫₀⁴ x dx = π[x²/2]₀⁴ = π(16/2−0) = 8π cubic units.
The exact area under the curve from a to b (shaded) is approximated by a few rectangles, the Riemann sum idea behind the definite integral.