We use cookies to distinguish you from other users and to provide you with a better experience on our websites. Close this message to accept cookies or find out how to manage your cookie settings.
Published online by Cambridge University Press: 03 November 2016
ABC is a triangle; BX, CX′ are equal arcs of the circumcircle taken in opposite senses from B and C. AX, AX′ are then said to be isogonally conjugate with respect to AB and AC. (The usual textbook definition is to say that the angles BAX, CAX′ are equal. The definition by equal arcs is used throughout this paper both because it has practical advantages and because it leads easily to theoretical development.)
page note 134 * Steiner’ ellipse for our purposes is defined by the areal equation yz+zx+xy=0. But we may remind readers that it is the ellipse which passes through the vertices. A, B, C of a triangle such that the tangent to it A is parallel to BC. Obviously its centre is the point G.
