About a century ago, the French artillery commandant Charbonnier envisioned an intriguing result on the trajectory of a projectile\nthat is moving under the forces of gravity and air resistance. In 2000, Groetsch discovered a significant gap in Charbonnierâ??s work\nand provided a valid argument for a certain special case. The goal of the present article is to establish a rigorous new approach to\nthe full result. For this, we develop a theory of those functions which can be sandwiched, in a natural way, by a pair of quadratic\npolynomials. It turns out that the convexity or concavity of the derivative plays a decisive role in this context.
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