Answer: tan x + C.
- A tan x + C
- B sec x + C
- C -tan x + C
- D sin x + C
Correct answer: A. tan x + C
Explanation: Integral of sec²x = tan x + C (since d/dx(tan x) = sec²x).
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.