A rectangle rests on the X axis, with its upper vertices tangent to the curve y=18-x^2. Find the largest area the rectangle can have.?
回答 (1)
2015-12-01 10:49 pm
A(x) = 2x*y = 2x*(18-x^2) = 36x - 2x^3
Set A'(x) = 36 - 6x^3 = 0
=> x = +-√6
=> max = A(√6) = 36*√6 - 2*6√6 = 24√6
Set A'(x) = 36 - 6x^3 = 0
=> x = +-√6
=> max = A(√6) = 36*√6 - 2*6√6 = 24√6
收錄日期: 2021-04-30 20:19:10
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