Exercises on Euclid and in modern geometry for the use of schools, private students, and junior university students (1881)
McDowell, James L · Cambridge, Deighton, Bell, and Co. · leaf 213
is plain that pencils in involution may be treatedsimilarly to ranges in involution, and that they possesskindred properties. If therefore three pairs of points bein involution, the pencil joining them to any point will bein involution, and conversely, any transversal meeting apencil in involution… … 216.] AND IN MODEKN GEOMETRY. 185 Join any point P with the extremities of the three diagonals.Then the pencil P.ABCCBA will be in involution. For, let PC meet AC in C and CA in C\ Then, evidently, {P. ABCC} = {P. ^<7C} = {<?. ^^CC,r} = {C. JSiiCC} = {P. £^(76} = {P. BACC\. But {P. BACC} =…
Geometry
Internet Archive · Wellesley College Library · Public Domain Mark 1.0. Free to use for anything.
