Answer: x³/3 + C.
- A x³/3 + C
- B 2x + C
- C x³ + C
- D 3x² + C
Correct answer: A. x³/3 + C
Explanation: ∫ xⁿ dx = xⁿ⁺¹/(n+1) + C, so ∫ x² dx = x³/3 + C.
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.