Let A1 be the bounded area enclosed by the curves y = x2 + 2, x + y = 8 and y-axis that lies in the first quadrant. Let A2 be the bounded area enclosed by the curves y = x2 + 2, y2 = x, x = 2, and y-axis that lies in the first quadrant. Then A1 - A2 is equal to
- 23(2 2 + 1)
- 23(3 2 + 1)
- 23( 2 + 1)
- 23(4 2 + 1)
Answer
(1) 23(2 2 + 1)
Solution
A1: y = x2 + 2 meets x + y = 8 where x2 + x - 6 = 0 x = 2 (first quadrant).
A1 = 02 [(8 - x) - (x2 + 2) ] dx = 02 (6 - x - x2) dx
A1 = 12 - 2 - 83 = 223
A2: between y = x2 + 2 (above) and y = x (below) from x = 0 to x = 2.
A2 = 02 (x2 + 2 - x ) dx = 83 + 4 - 23(2)3/2
A2 = 203 - 4 23
A1 - A2 = 223 - 203 + 4 23 = 23(2 2 + 1)
Answer: (1)