Proof that x*y requires reference length: if x is reference length then x*y is y
if y is reference length then x*y is x If we do not know the reference length and if x and y are different then we do not know if x*y is x or y but we know that it could be either of those. -- Raul On Thu, Jul 14, 2016 at 1:19 PM, Roger Hui <[email protected]> wrote: > Given line segments x and y, construct (using compass and straight edge) > line segments having the following values: > > x+y > x-y > x*y > x%y > > The first two are immediate. I have proven that x%y is impossible if you > are not given a reference length 1 (or some other reference length from > which to construct 1). > > The problem is, prove or disprove that you construct x*y without using 1. > (Constructing x*y and x%y _with_ 1 are pretty easy.) > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
