Answer: x + x² + x³/3 + C.
- A x + x² + x³/3 + C
- B x + x² + x³ + C
- C (1+x)³/3 + C
- D (1+x)³ + C
Correct answer: A. x + x² + x³/3 + C
Explanation: Expand: 1 + 2x + x². Integrate: x + x² + 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.