8. What is the area of the largest rectangle that can be inscribed in the region bounded by y = 3 – x2 and the x-axis?
|
A. 1 |
B. 2 |
C. 9/4 |
|
D. 4 |
E. 4(3)1/2 |
Solution: The answer is D
Consider the following graph of the region described above with an inscribed rectangle of length L = 2x and width W = y = 3 – x2:

Since the area A, of any rectangle, is given by the product of its length and width,
![]()
![]()
So that the maximum area is given by, evaluating A(x) at the critical points and choosing the maximum value. The critical points are found by solving the equation, A’(x)=0, as follows:
![]()
Hence, the largest rectangle that can be inscribed in the above region is,
![]()