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Putnam 1953 B4

Source: Putnam 1953

July 16, 2022
Putnamgeometry3D geometrytangent

Problem Statement

Determine the equations of a surface in three-dimensional cartesian space which has the following properties: (a) it passes through the point (1,1,1)(1,1,1) and (b) if the tangent plane is drawn at any point PP and X,Y,ZX,Y, Z are the intersections of this plane with the x,yx, y and zāˆ’z-axis respectively, then PP is the orthocenter of the triangle XYZ.XYZ.