Manipal MET2014MathematicsBinomial Theorem
Middle term in the expansion of (x^2+ 1 x^2 +2 )^n is
Options
- An! (n!)^2
- B(2 n!) (n!)^2
- C(2 n-1)! n!
- D(2 n)! n!
Correct answer
B. (2 n!) (n!)^2
Step-by-step solution
The given expression is aligned (x^2+ 1 x^2 +2 )^n & = [ (x+ 1 x )^2 ]^n & = (x+ 1 x )^ 2 n aligned The binomial contains (2 n+1) terms in its expansion. The middle term is T_ n+1 . aligned T_ n+1 & = ^ 2 n C_n(x)^ 2 n-n ( 1 x )^n & = ^ 2 n C_n & = (2 n)! (2 n-n)!n! = (2 n)! (n!)^2 aligned