Answer: x² + C.
- A 2 + C
- B x² + C
- C 2x² + C
- D x + C
Correct answer: B. x² + C
Explanation: Integral of 2x = 2 × x²/2 = x² + 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.