Answer: sin x + C.
- A sin x + C
- B -sin x + C
- C cos x + C
- D -cos x + C
Correct answer: A. sin x + C
Explanation: Integral of cos x = sin x + C (since d/dx(sin x) = cos x).
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.