Manipal MET2017MathematicsBinomial Theorem
The middle term of ( x - 1 x )^6 is
Options
- A-20
- B-1
- C1
- DNone of these
Correct answer
A. -20
Step-by-step solution
Middle term is ( n 2 +1 ) th term for n even. Middle term = ( 6 2 +1 )=4 th term aligned T₄ & = ^6 C₃( x )^3 (- 1 x )⁶⁻³ & = 6! 3!3! ( x )^3 (-1)^3 ( x )^3 & = -6 5 4 6 & =-20 aligned