MathDB
Putnam 1941 A5

Source: Putnam 1941

February 23, 2022
Putnamconicsparabola

Problem Statement

The line LL is parallel to the plane y=zy=z and meets the parabola 2x=y2,z=02x=y^2 ,z=0 and the parabola 3x=z2,y=03x=z^2, y=0. Prove that if LL moves freely subject to these constraints then it generates the surface x=(y−z)(y2−z3)x=(y-z)\left(\frac{y}{2}-\frac{z}{3}\right).
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