In the first quadrant representative rectangle so that has a vertex at the origin and the opposite vertex on the parabola y = x ^ 2 +3. Determine the dimensions of the rectangle so that its area is maximized.

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anonymous · Answer

@hartnn 
@hba

hartnn · Answer

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so the rectangle has dimension of $x \times (x^2+3)$
so, your area $A =x \times (x^2+3)=x^3+3x$
can you maximize this ? 
differentiate it and set A'=0 to get values of 'x'