If (1+x+x2)6n=a0+a1x+....then(a0+a3+a6+.....)=(a)36n-1(B)36n+1(c)36n-1(D)36n+1-1

HI VAIBHAV,

You can do this problem using a short trick,which is used generally to solve objective problems involving n,this will save ur time and u'll get the correct answer.Do onething put n=1/3,so expression becomes (1+x+x²)² =1+2x+3x² +2x³+x⁴ now a₀+a₃=1+2=3...........now solve all the answers for n=1/3 u'll find that option (a)3^6n-1=3 is the correct answer.