Problem C. 925. (January 2008)
C. 925. Show that the expression
has a constant value for all x and y for which it is meaningful and x+y=1.
(5 pont)
Deadline expired on 15 February 2008.
Statistics:
225 students sent a solution.  
5 points:  206 students. 
4 points:  1 student. 
3 points:  1 student. 
2 points:  2 students. 
1 point:  3 students. 
0 point:  5 students. 
Unfair, not evaluated:  7 solutions. 
