If three successive terms of a geometric sequence with ratio r correspond to the lengths of the three sides of a triangle, then determine whether or not [r]+[-r]=-1.

[x] is the greatest integer ≤ x.

Order the sides from greatest to smallest; obviously r is between 0 and 1, and then
[r]=0 and [-r]=-1.

Posted by e.g. on 2007-03-19 08:43:47