If the coefficient of $(2r + 1)th$ term and $(r + 2)th$ term in the expansion of ${(1 + x)}^{43}$ are equal, then $r$ is equal to

Question

Dr. Abubacker · Accepted Answer

(b)
Given coefficient of $(2x + 1)$th term$=$coefficient of $(r + 2)$th term
$\Longrightarrow \ \ ^{43}C_{2r} = \ ^{43}C_{r + 1}$
$\Longrightarrow 2r + (r + 1) = 43\ or\ 2r = r + 1$
$\Longrightarrow r = 14\ or\ r = 1$

Q. If the coefficient of $(2r + 1)th$ term and $(r + 2)th$ term in the expansion of ${(1 + x)}^{43}$ are equal, then $r$ is equal to

Explanation

Reviewed by Dr. Abubacker

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