Find the two middle terms in the expansion of :
For ,
a= x4, and n=11
As n is odd, there are two middle terms i.e.
II. and II.
General term tr+1 is given by,
I. The first middle term is
Therefore, for the 6th middle term, r=5
Therefore, the first middle term is
= - 462. x9
II. The second middle term is
Therefore, for the 7th middle term, r=6
Therefore, the second middle term is
………
= 462. x2