Number of greatest binomial coefficients in the expansion of (1+x)2n and (1+x)2n+1 are p and q respectively (where n is a positive integer). Find the value of p+2q
Middle term has the greatest binomial coefficient in any binomial expansion. When the power is even (in the case of (1+x)2n), there will be only one middle term
⇒ Only one term with greatest binomial coefficient.
⇒ p=1
When the power is odd (in the case of (1+x)2n), there will be two middle terms terms (or two terms with greatest binomial coefficient)
⇒ q=2
⇒ p+2q=1+4=5