BITSAT2011MathematicsBinomial TheoremActual
The term independent of (x ) in the expansion of ( (9 x - 1 3 x )¹⁸, x > 0 ), is a times the corresponding binomial coefficient. Then a is
Options
- A3
- B(1 / 3 )
- C(-1 / 3 )
- DNone of these
Correct answer
D. None of these
Step-by-step solution
( aligned T _ r +1 & = ¹⁸ C _ r (9 x )^ 18- r (- 1 3 x )^ r & =(- r )^ r ¹⁸ C _ r 9^ 18- 3 r 2 x ^ 18- 3 r 2 aligned ) is independent of ( x ) provided ( r =12 ) and then ( a =1 ).