NDA2022MathematicsBinomial TheoremActual
Paragraph: Consider the binomial expansion of (p+q x)^9 : Question: What is the ratio of the coefficients of middle terms in the expansion (when expanded in ascending powers of x )?
Options
- Ap q
- Bp q
- C4 p 5 q
- D1 (p q)
Correct answer
B. p q
Step-by-step solution
Middle terms aligned & T₅=T_ 4+1 = ^9 C₄ p^5 q^4 x^4 & T₆=T_ 5+1 = ^9 C₅ p^4 q^5 x^5 & Ratio of coefficients = ^9 C₅ p^5 q^4 ^9 C₄ p^4 q^5 = p q aligned