यदि `(1+x+x^(2))^(n)=underset(r=0)overset(2n)sum a_(r)x^(r )`, हो तो सिद्ध कीजिये की `(a) a_(r)=a_(2n-r) ` (b) `underset(r=0)overset(n-1)sum a_(r)=1/2 (3^(n)-a_(n))`

Answer

(a) `a_(r), 0 le r le 2n` (b) `1/3 (3^(n)-a_(n))`