

We wish to place the parabola 9x^2+16y^2+24xy+22x+46y+9=0 such that its vertex is at the origin an its focus is on the positive xaxis. We first creat...



Let B be the focus of the parabola, and D be the intersection between a tangent whose point of contact is C and the parabola axis. The triangle BDC i...



If we take the parabola Y=aX2 and look at the length of the horizontal chord through the focus, we find this is 1/a. Salmon calls this the parameter ...



If CD is a chord of a parabola and E its intersection with the directrix, then BE externally bisects the angle CBD.



Draw a tangent to a parabola and a line from the focus to that tangent. Draw another line from the tangency point to the vertex, and keep the angle be...



We examine the locus of the intersection of the perpendicular from the focus to the tangent with the horizontal from the point of contact and find it ...



The area of the triangle formed by 3 tangents is half the area of the triangle formed by their points of contact.



We use the evolute.



