In the binomial expansion of ( a − b ) n , n ≥ 5 , the sum of 5 th and 6 th terms is zero, then b a equals

n C 4 a n − 4 ( − b ) 4 + n C 5 a n − 5 ( − b ) 5 = 0 ⇒ ( b a ) = 5 n − 5 + 1 .

Mathematics - Binomial Theorem Question with Solution | TestHub

MathematicsBinomial TheoremGeneralMedium2 minPYQ_2007

MathematicsMediumsingle choice

In the binomial expansion of $(a - b)^{n}, n \geq 5$ , the sum of $5^{th}$ and $6^{th}$ terms is zero, then $\frac{a}{b}$ equals

Answer:

Solution:

$^{n} C_{4} a^{n - 4} (- b)^{4} +^{n} C_{5} a^{n - 5} (- b)^{5} = 0$ $\Rightarrow (\frac{a}{b}) = \frac{n - 5 + 1}{5}$ .

Stream:JEESubject:MathematicsTopic:Binomial TheoremSubtopic:General

⏱ 2mℹ️ Source: PYQ_2007

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