[JEE Main 2007] $\binom{20}0-\binom{20}1+\binom{20}2-\cdots+\binom{20}{10}$ equals
$\binom{20}0-\binom{20}1+\binom{20}2-\cdots+\binom{20}{10}$ equals
(a) $0$
(b) $\binom{20}{10}$
(c) $-\binom{20}{10}$
(d) $\dfrac12\binom{20}{10}$
1 Answer
VAVidaara Admin
✓ Vidaara Team
✓ Accepted
· 1mo ago
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Correct answer: (d) $\dfrac12\binom{20}{10}$
Using the symmetry of the full alternating sum (which is $0$), the partial sum to the middle term is $\frac12\binom{20}{10}$.
JEE Main 2007 · Binomial Theorem — verified solution by the Vidaara Team.
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