kindly help in que

2...help pleasee

. kindly answer fast

Dear student 

Let(1+x^2)^2(1+x)^n = Σak *x^k 
By binomial theorem 
(1+2x^2 + x^4 ) (nCo(1)^n-0 +nC1 (1)^n-1 x + nC2 (1)^n-2 x^2 + ...............
(1+2x^2+x^4) (nCo + nC1 x +nC2x^2 + ........
 (1+ 2x^2 + x^4) (1+nx+n(n-1)/2 x^2 +.......)
Foe Ao we need cofficient of x^0 
coff of x^0 = Ao 
coff of x = A1 
2+ n(n-1)/2 is cofficient of x^2 = A2 
Ao , A1 , A2 are in AP 
A + A2 /2 = A1 
On solving n = 2,3