(a2001 + b2001).(a+ b) - (a2000 + b2000).ab
= a2002 + b2002
ð
(a+ b) – ab = 1=>(a – 1).(b – 1) = 0
ð
a = 1 hoÆc b = 1
Víi a = 1 =>
b2000 = b2001 => b = 1 hoÆc b = 0 (lo¹i)
Víi b = 1 =>
a2000 = a2001 => a = 1 hoÆc a = 0 (lo¹i)
VËy a = 1; b = 1 => a2011 + b2011 = 2