In the binomial coefficients of (1 + x)^n, the coefficients of the 5th, 6th and 7 terms are in AP. Find all values of n.

Question

In the binomial coefficients of (1 + x)ⁿ, the coefficients of the 5^th, 6^th and 7^th terms are in AP. Find all values of n.

Answer 1

Coefficient of T₅, T₆,T₇ are in AP.

⇒ (n – 1)(n – 14) = 0 

∴ n = 7 , 14