Question

if the coffecient of $a^{r-1}$,$a^{r}$,$a^{r+1}$ in the bionomial expansion of $1+a^{n}$ are in a.p.
prove that $n^{2}$ -n(4r+1)+$4r^{2}$ -2 =0

Answer 1

Answer:

the answer is 5

Step-by-step explanation: