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A rectangle is inscribed in the ellipse x^2/400 + y^2/225 = 1 with its sides parallel to the axes of the ellipse (Figure Q5). Find the dimensions of the rectangle of maximum perimeter which can be so inscribed.

How do i find the dimensions of the rectangle of maximum perimeter. I honestly have no clue where i should start, It would be really helpful if someone can provide a step-by-step for this solution. (The question and diagram is linked below)

Thanks in advance

Question & Diagram


marked as duplicate by Aretino, user99914, Namaste calculus Jul 28 '18 at 0:04

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