A possible origin of quadratic equations and solutions

It has been conjectured by some authors, notably N. Katz, A History of Mathematics, that the origin of the quadratic formula may have resulted from the confusion between the knowing the perimeter and knowing the area of a rectangular region. Here is how the argument unfolds.

Suppose we know the perimeter of a rectangle to be $P=2p$. Thus $p$ is the sum of the length and width. What is the area? Well, the two sides $x$ and $y$ can be written as
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Thus the area is
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Solving we obtain
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This gives
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This is the form of the solution of the quadratic equation $x^{2}+q=px$.




If it was the case that some people believe the area depended only on the perimeter, this gives a method of finding a variety of rectangles having the same perimeter but different areas. It is just conjecture, but one with a reasonable plausibility. In any event, the necessity of solving quadratics can arise from simple area calculations.

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