A rectangle has its base on the -axis and its two upper vertices on the curve , symmetric about the -axis. The maximum possible area is:
Answer and explanation
Correct answer: A.
- Step 1: With vertices at , the area is .
- Step 2: gives for .
- Step 3: .
Answer
32.
Why not the others: uses half the base; and come from using the wrong or forgetting the factor 2 for the full base.
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